Vulnerability-Lookup

GHSA-72RP-5PW2-WRGC

Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-09-14 15:32

Details

In the Linux kernel, the following vulnerability has been resolved:

auxdisplay: charlcd: cancel backlight work on registration failure

With CONFIG_CHARLCD_BL_FLASH, charlcd_init() schedules bl_work before charlcd_register() calls misc_register(). If registration fails, the caller frees the charlcd object while delayed work still contains its address.

Add charlcd_deinit() to cancel the delayed work and turn the backlight off. Use it for both registration rollback and normal unregistration.

Severity

7.8 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-89585"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-11T20:19:42Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nauxdisplay: charlcd: cancel backlight work on registration failure\n\nWith CONFIG_CHARLCD_BL_FLASH, charlcd_init() schedules bl_work before\ncharlcd_register() calls misc_register(). If registration fails, the\ncaller frees the charlcd object while delayed work still contains its\naddress.\n\nAdd charlcd_deinit() to cancel the delayed work and turn the backlight\noff. Use it for both registration rollback and normal unregistration.",
  "id": "GHSA-72rp-5pw2-wrgc",
  "modified": "2026-09-14T15:32:30Z",
  "published": "2026-09-11T21:31:33Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89585"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/22586432c1aba89d9bd33f3173408dac830f220b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6eaed64a32e550daf0dc9549742b3ab9e41d984f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/84858671842ae5857b9ed1202b62f9045373dcd1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cd97b3c68fe3c06c8067cc59d7dff976c5b7ea04"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e3e3bf40916c1e810df03958cfa7ba6883cdce79"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fe7ba73dde94c5f413b1588cd444b49105015dda"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ff2fb3c1e60cb247ea3e28c0ea0bea81c18f7755"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-89585 (GCVE-0-2026-89585)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:44 – Updated: 2026-09-14 12:01

Title

auxdisplay: charlcd: cancel backlight work on registration failure

Summary

In the Linux kernel, the following vulnerability has been resolved: auxdisplay: charlcd: cancel backlight work on registration failure With CONFIG_CHARLCD_BL_FLASH, charlcd_init() schedules bl_work before charlcd_register() calls misc_register(). If registration fails, the caller frees the charlcd object while delayed work still contains its address. Add charlcd_deinit() to cancel the delayed work and turn the backlight off. Use it for both registration rollback and normal unregistration.

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

7 references

URL	Tags
https://git.kernel.org/stable/c/cd97b3c68fe3c06c8…
https://git.kernel.org/stable/c/22586432c1aba89d9…
https://git.kernel.org/stable/c/6eaed64a32e550daf…
https://git.kernel.org/stable/c/fe7ba73dde94c5f41…
https://git.kernel.org/stable/c/84858671842ae5857…
https://git.kernel.org/stable/c/ff2fb3c1e60cb247e…
https://git.kernel.org/stable/c/e3e3bf40916c1e810…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 39f8ea46724efbed3ca021863a22337c31be264c , < cd97b3c68fe3c06c8067cc59d7dff976c5b7ea04 (git) Affected: 39f8ea46724efbed3ca021863a22337c31be264c , < 22586432c1aba89d9bd33f3173408dac830f220b (git) Affected: 39f8ea46724efbed3ca021863a22337c31be264c , < 6eaed64a32e550daf0dc9549742b3ab9e41d984f (git) Affected: 39f8ea46724efbed3ca021863a22337c31be264c , < fe7ba73dde94c5f413b1588cd444b49105015dda (git) Affected: 39f8ea46724efbed3ca021863a22337c31be264c , < 84858671842ae5857b9ed1202b62f9045373dcd1 (git) Affected: 39f8ea46724efbed3ca021863a22337c31be264c , < ff2fb3c1e60cb247ea3e28c0ea0bea81c18f7755 (git) Affected: 39f8ea46724efbed3ca021863a22337c31be264c , < e3e3bf40916c1e810df03958cfa7ba6883cdce79 (git)
Linux	Linux	Affected: 4.12 Unaffected: 0 , < 4.12 (semver) Unaffected: 5.15.221 , ≤ 5.15.* (semver) Unaffected: 6.1.188 , ≤ 6.1.* (semver) Unaffected: 6.6.157 , ≤ 6.6.* (semver) Unaffected: 6.12.109 , ≤ 6.12.* (semver) Unaffected: 6.18.50 , ≤ 6.18.* (semver) Unaffected: 7.2.4 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/auxdisplay/charlcd.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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              "status": "affected",
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            {
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              "versionType": "git"
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              "versionType": "git"
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              "status": "affected",
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              "versionType": "git"
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          ]
        },
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.12"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "6.12.109",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "4.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "4.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.157",
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nauxdisplay: charlcd: cancel backlight work on registration failure\n\nWith CONFIG_CHARLCD_BL_FLASH, charlcd_init() schedules bl_work before\ncharlcd_register() calls misc_register(). If registration fails, the\ncaller frees the charlcd object while delayed work still contains its\naddress.\n\nAdd charlcd_deinit() to cancel the delayed work and turn the backlight\noff. Use it for both registration rollback and normal unregistration."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - charlcd_register() is reached only from local auxdisplay probe (hd44780 platform, lcd2s I2C, panel parport) on character LCDs in embedded, industrial, and appliance systems; there is no network or USB-host packet path into this misc-registration error path.\nAC:L - CONFIG_CHARLCD_BL_FLASH is the default, so charlcd_init() always queues bl_work (L* poke, 4s) before misc_register(); a second charlcd consumer or LCD_MINOR 156 collision makes registration fail deterministically, then the work runs on the freed object with no attacker-uncontrollable race.\nPR:L - On multi-display or mixed hd44780/lcd2s/panel systems the second probe runs automatically at boot without init-namespace root, and an unprivileged local user can spray the heap in the 4s window; embedded/kiosk sysfs bind is also not strictly root-only. Uncertain vs High, so Low.\nUI:N - The UAF is armed during driver probe and consumed by the kernel workqueue; no victim needs to open /dev/lcd, mount a filesystem, or take any other interactive action.\nS:U - The delayed-work UAF corrupts in-kernel charlcd_priv/work_struct heap state and can escalate only within the host kernel; it does not cross a VM, IOMMU, or sandbox boundary.\nC:H - charlcd_bl_off() does container_of() on the freed delayed_work and reads priv fields, including lcd.ops, from reclaimable slab, giving a use-after-free kernel read primitive.\nI:H - The same callback invokes priv-\u003elcd.ops-\u003ebacklight on the freed object, so reclaiming the slab with a forged ops table yields a kernel function-pointer call, arbitrary write, and control-flow hijack.\nA:H - Running delayed work after charlcd_free() oopses or panics via mutex_lock on freed bl_tempo_lock or a wild ops pointer, even when the UAF is not fully exploited."
            }
          ]
        }
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      "providerMetadata": {
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        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/22586432c1aba89d9bd33f3173408dac830f220b"
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        },
        {
          "url": "https://git.kernel.org/stable/c/84858671842ae5857b9ed1202b62f9045373dcd1"
        },
        {
          "url": "https://git.kernel.org/stable/c/ff2fb3c1e60cb247ea3e28c0ea0bea81c18f7755"
        },
        {
          "url": "https://git.kernel.org/stable/c/e3e3bf40916c1e810df03958cfa7ba6883cdce79"
        }
      ],
      "title": "auxdisplay: charlcd: cancel backlight work on registration failure",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89585",
    "datePublished": "2026-09-11T19:44:50.592Z",
    "dateReserved": "2026-09-11T19:38:34.729Z",
    "dateUpdated": "2026-09-14T12:01:12.853Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

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