Vulnerability-Lookup

FKIE_CVE-2026-90339

Vulnerability from fkie_nvd - Published: 2026-09-17 17:17 - Updated: 2026-09-17 17:17

Severity

Summary

In the Linux kernel, the following vulnerability has been resolved: powerpc/syscall: Fix syscall skip handling for seccomp and ptrace After enabling GENERIC_ENTRY on PowerPC, syscall_enter_from_user_mode() returns -1 as a sentinel to signal that seccomp or ptrace has intercepted the syscall and already set a return value via syscall_set_return_value(). system_call_exception() was not handling this sentinel, and since -1UL is >= NR_syscalls, the code fell into the out-of-range path and returned -ENOSYS, overwriting the errno already placed in regs->gpr[3]. The naive fix of checking r0 == -1L before the NR_syscalls bounds check is ambiguous: a user legitimately calling syscall(-1) also produces r0 == -1L, and a tracer intercepting such a call would have its injected return value silently discarded. Fix this by introducing a thread flag that is set whenever syscall_set_return_value() explicitly updates the return value. In system_call_exception(), check and clear this flag before dispatching the syscall, and return the preset value directly when it is present. This ensures that an explicitly supplied return value always suppresses syscall execution, regardless of the syscall number. This handles all seccomp actions correctly: - SECCOMP_RET_ERRNO, SECCOMP_RET_TRACE (no tracer), SECCOMP_RET_USER_NOTIF: all call syscall_set_return_value(), flag is set, injected value returned. - SECCOMP_RET_TRAP, SECCOMP_RET_KILL: call syscall_rollback() and deliver a signal; flag is not set, but the process is dying so the return value is irrelevant. The fix covers both ppc32 and ppc64 with no #ifdefs.

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/19b54740e2e1102c7d48553d9e0347c1f6af22b0
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/69cb2be898be6d5826cacd1a628f6945a24480b6

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/powerpc/include/asm/syscall.h",
            "arch/powerpc/include/asm/thread_info.h",
            "arch/powerpc/kernel/syscall.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "19b54740e2e1102c7d48553d9e0347c1f6af22b0",
              "status": "affected",
              "version": "bee25f97ad24641df55cb3887eb5bfcb2b9d8fbc",
              "versionType": "git"
            },
            {
              "lessThan": "69cb2be898be6d5826cacd1a628f6945a24480b6",
              "status": "affected",
              "version": "bee25f97ad24641df55cb3887eb5bfcb2b9d8fbc",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/powerpc/include/asm/syscall.h",
            "arch/powerpc/include/asm/thread_info.h",
            "arch/powerpc/kernel/syscall.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.2"
            },
            {
              "lessThan": "7.2",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/syscall: Fix syscall skip handling for seccomp and ptrace\n\nAfter enabling GENERIC_ENTRY on PowerPC, syscall_enter_from_user_mode()\nreturns -1 as a sentinel to signal that seccomp or ptrace has intercepted\nthe syscall and already set a return value via syscall_set_return_value().\nsystem_call_exception() was not handling this sentinel, and since -1UL\nis \u003e= NR_syscalls, the code fell into the out-of-range path and returned\n-ENOSYS, overwriting the errno already placed in regs-\u003egpr[3].\n\nThe naive fix of checking r0 == -1L before the NR_syscalls bounds check\nis ambiguous: a user legitimately calling syscall(-1) also produces r0 ==\n-1L, and a tracer intercepting such a call would have its injected return\nvalue silently discarded.\n\nFix this by introducing a thread flag that is set whenever\nsyscall_set_return_value() explicitly updates the return value. In\nsystem_call_exception(), check and clear this flag before dispatching\nthe syscall, and return the preset value directly when it is present.\nThis ensures that an explicitly supplied return value always suppresses\nsyscall execution, regardless of the syscall number.\n\nThis handles all seccomp actions correctly:\n\n  - SECCOMP_RET_ERRNO, SECCOMP_RET_TRACE (no tracer), SECCOMP_RET_USER_NOTIF:\n    all call syscall_set_return_value(), flag is set, injected value returned.\n  - SECCOMP_RET_TRAP, SECCOMP_RET_KILL: call syscall_rollback() and deliver\n    a signal; flag is not set, but the process is dying so the return value\n    is irrelevant.\n\nThe fix covers both ppc32 and ppc64 with no #ifdefs."
    }
  ],
  "id": "CVE-2026-90339",
  "lastModified": "2026-09-17T17:17:32.520",
  "metrics": {},
  "published": "2026-09-17T17:17:32.520",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/19b54740e2e1102c7d48553d9e0347c1f6af22b0"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/69cb2be898be6d5826cacd1a628f6945a24480b6"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

CVE-2026-90339 (GCVE-0-2026-90339)

Vulnerability from cvelistv5 – Published: 2026-09-17 16:08 – Updated: 2026-09-17 16:08

Title

powerpc/syscall: Fix syscall skip handling for seccomp and ptrace

Summary

Severity

No CVSS data available.

Assigner

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/19b54740e2e1102c7…
https://git.kernel.org/stable/c/69cb2be898be6d582…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: bee25f97ad24641df55cb3887eb5bfcb2b9d8fbc , < 19b54740e2e1102c7d48553d9e0347c1f6af22b0 (git) Affected: bee25f97ad24641df55cb3887eb5bfcb2b9d8fbc , < 69cb2be898be6d5826cacd1a628f6945a24480b6 (git)
Linux	Linux	Affected: 7.2 Unaffected: 0 , < 7.2 (semver) Unaffected: 7.2.6 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/powerpc/include/asm/syscall.h",
            "arch/powerpc/include/asm/thread_info.h",
            "arch/powerpc/kernel/syscall.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "19b54740e2e1102c7d48553d9e0347c1f6af22b0",
              "status": "affected",
              "version": "bee25f97ad24641df55cb3887eb5bfcb2b9d8fbc",
              "versionType": "git"
            },
            {
              "lessThan": "69cb2be898be6d5826cacd1a628f6945a24480b6",
              "status": "affected",
              "version": "bee25f97ad24641df55cb3887eb5bfcb2b9d8fbc",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/powerpc/include/asm/syscall.h",
            "arch/powerpc/include/asm/thread_info.h",
            "arch/powerpc/kernel/syscall.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.2"
            },
            {
              "lessThan": "7.2",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.6",
                  "versionStartIncluding": "7.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "7.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/syscall: Fix syscall skip handling for seccomp and ptrace\n\nAfter enabling GENERIC_ENTRY on PowerPC, syscall_enter_from_user_mode()\nreturns -1 as a sentinel to signal that seccomp or ptrace has intercepted\nthe syscall and already set a return value via syscall_set_return_value().\nsystem_call_exception() was not handling this sentinel, and since -1UL\nis \u003e= NR_syscalls, the code fell into the out-of-range path and returned\n-ENOSYS, overwriting the errno already placed in regs-\u003egpr[3].\n\nThe naive fix of checking r0 == -1L before the NR_syscalls bounds check\nis ambiguous: a user legitimately calling syscall(-1) also produces r0 ==\n-1L, and a tracer intercepting such a call would have its injected return\nvalue silently discarded.\n\nFix this by introducing a thread flag that is set whenever\nsyscall_set_return_value() explicitly updates the return value. In\nsystem_call_exception(), check and clear this flag before dispatching\nthe syscall, and return the preset value directly when it is present.\nThis ensures that an explicitly supplied return value always suppresses\nsyscall execution, regardless of the syscall number.\n\nThis handles all seccomp actions correctly:\n\n  - SECCOMP_RET_ERRNO, SECCOMP_RET_TRACE (no tracer), SECCOMP_RET_USER_NOTIF:\n    all call syscall_set_return_value(), flag is set, injected value returned.\n  - SECCOMP_RET_TRAP, SECCOMP_RET_KILL: call syscall_rollback() and deliver\n    a signal; flag is not set, but the process is dying so the return value\n    is irrelevant.\n\nThe fix covers both ppc32 and ppc64 with no #ifdefs."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-17T16:08:50.990Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/19b54740e2e1102c7d48553d9e0347c1f6af22b0"
        },
        {
          "url": "https://git.kernel.org/stable/c/69cb2be898be6d5826cacd1a628f6945a24480b6"
        }
      ],
      "title": "powerpc/syscall: Fix syscall skip handling for seccomp and ptrace",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90339",
    "datePublished": "2026-09-17T16:08:50.990Z",
    "dateReserved": "2026-09-11T19:38:34.804Z",
    "dateUpdated": "2026-09-17T16:08:50.990Z",
    "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.

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