CVE-2026-80578 (GCVE-0-2026-80578)
Vulnerability from cvelistv5 – Published: 2026-08-26 14:37 – Updated: 2026-08-26 14:37
VLAI
EPSS
VEX
Title
fbdev: core: Fix pointer desynchronization in fb_io_read()
Summary
In the Linux kernel, the following vulnerability has been resolved:
fbdev: core: Fix pointer desynchronization in fb_io_read()
In fb_io_read(), if copy_to_user() performs a partial copy (e.g., due to
a faulty user buffer), the loop adjusts the chunk size 'c' and updates
the remaining 'count'. However, the hardware 'src' pointer has already
been eagerly advanced by the original chunk size.
If the loop is allowed to continue, the read will resume from an
incorrect, over-advanced offset. Since the remaining 'count' was only
decremented by the successful bytes, this desynchronization causes the
next iterations to execute more hardware reads than originally bounded,
eventually leading to out-of-bounds I/O reads.
Fix this by breaking out of the loop immediately upon a partial
copy_to_user(). A partial copy indicates a faulty user buffer, making
subsequent read attempts futile. Breaking out ensures we return the
number of successfully read bytes without risking out-of-bounds hardware
accesses in subsequent mismatched iterations.
Severity
No CVSS data available.
Assigner
References
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff , < 42bc07b4e5a3c8a02a433388f562a8f46d093e11
(git)
Affected: 6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff , < 42a6d8126c194133eafab2b0fd5c8668ebfcba5b (git) Affected: 6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff , < 7ff87a01ae3a8cd0208f7499386998223a8b5dba (git) Affected: 6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff , < 7110b7b794a2aac2c5cf8eb06ebf2af724c74d50 (git) Affected: 6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff , < 81cc73be40c6f028f1ee3f438ace46afe666dbae (git) |
guessed | |
| Linux | Linux |
Affected:
6.5
Unaffected: 0 , < 6.5 (semver) Unaffected: 6.6.153 , ≤ 6.6.* (semver) Unaffected: 6.12.105 , ≤ 6.12.* (semver) Unaffected: 6.18.46 , ≤ 6.18.* (semver) Unaffected: 7.1.10 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix) |
guessed |
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/video/fbdev/core/fb_io_fops.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "42bc07b4e5a3c8a02a433388f562a8f46d093e11",
"status": "affected",
"version": "6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff",
"versionType": "git"
},
{
"lessThan": "42a6d8126c194133eafab2b0fd5c8668ebfcba5b",
"status": "affected",
"version": "6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff",
"versionType": "git"
},
{
"lessThan": "7ff87a01ae3a8cd0208f7499386998223a8b5dba",
"status": "affected",
"version": "6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff",
"versionType": "git"
},
{
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"status": "affected",
"version": "6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff",
"versionType": "git"
},
{
"lessThan": "81cc73be40c6f028f1ee3f438ace46afe666dbae",
"status": "affected",
"version": "6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/video/fbdev/core/fb_io_fops.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.5"
},
{
"lessThan": "6.5",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.153",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.105",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.46",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.10",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.153",
"versionStartIncluding": "6.5",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.105",
"versionStartIncluding": "6.5",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.46",
"versionStartIncluding": "6.5",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.10",
"versionStartIncluding": "6.5",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "6.5",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfbdev: core: Fix pointer desynchronization in fb_io_read()\n\nIn fb_io_read(), if copy_to_user() performs a partial copy (e.g., due to\na faulty user buffer), the loop adjusts the chunk size \u0027c\u0027 and updates\nthe remaining \u0027count\u0027. However, the hardware \u0027src\u0027 pointer has already\nbeen eagerly advanced by the original chunk size.\n\nIf the loop is allowed to continue, the read will resume from an\nincorrect, over-advanced offset. Since the remaining \u0027count\u0027 was only\ndecremented by the successful bytes, this desynchronization causes the\nnext iterations to execute more hardware reads than originally bounded,\neventually leading to out-of-bounds I/O reads.\n\nFix this by breaking out of the loop immediately upon a partial\ncopy_to_user(). A partial copy indicates a faulty user buffer, making\nsubsequent read attempts futile. Breaking out ensures we return the\nnumber of successfully read bytes without risking out-of-bounds hardware\naccesses in subsequent mismatched iterations."
}
],
"providerMetadata": {
"dateUpdated": "2026-08-26T14:37:36.722Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/42bc07b4e5a3c8a02a433388f562a8f46d093e11"
},
{
"url": "https://git.kernel.org/stable/c/42a6d8126c194133eafab2b0fd5c8668ebfcba5b"
},
{
"url": "https://git.kernel.org/stable/c/7ff87a01ae3a8cd0208f7499386998223a8b5dba"
},
{
"url": "https://git.kernel.org/stable/c/7110b7b794a2aac2c5cf8eb06ebf2af724c74d50"
},
{
"url": "https://git.kernel.org/stable/c/81cc73be40c6f028f1ee3f438ace46afe666dbae"
}
],
"title": "fbdev: core: Fix pointer desynchronization in fb_io_read()",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-80578",
"datePublished": "2026-08-26T14:37:36.722Z",
"dateReserved": "2026-08-26T14:34:25.769Z",
"dateUpdated": "2026-08-26T14:37:36.722Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"nvd": "{\"cve\":{\"id\":\"CVE-2026-80578\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-26T15:17:13.880\",\"lastModified\":\"2026-08-26T15:17:13.880\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nfbdev: core: Fix pointer desynchronization in fb_io_read()\\n\\nIn fb_io_read(), if copy_to_user() performs a partial copy (e.g., due to\\na faulty user buffer), the loop adjusts the chunk size \u0027c\u0027 and updates\\nthe remaining \u0027count\u0027. However, the hardware \u0027src\u0027 pointer has already\\nbeen eagerly advanced by the original chunk size.\\n\\nIf the loop is allowed to continue, the read will resume from an\\nincorrect, over-advanced offset. Since the remaining \u0027count\u0027 was only\\ndecremented by the successful bytes, this desynchronization causes the\\nnext iterations to execute more hardware reads than originally bounded,\\neventually leading to out-of-bounds I/O reads.\\n\\nFix this by breaking out of the loop immediately upon a partial\\ncopy_to_user(). A partial copy indicates a faulty user buffer, making\\nsubsequent read attempts futile. Breaking out ensures we return the\\nnumber of successfully read bytes without risking out-of-bounds hardware\\naccesses in subsequent mismatched iterations.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"drivers/video/fbdev/core/fb_io_fops.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff\",\"lessThan\":\"42bc07b4e5a3c8a02a433388f562a8f46d093e11\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff\",\"lessThan\":\"42a6d8126c194133eafab2b0fd5c8668ebfcba5b\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff\",\"lessThan\":\"7ff87a01ae3a8cd0208f7499386998223a8b5dba\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff\",\"lessThan\":\"7110b7b794a2aac2c5cf8eb06ebf2af724c74d50\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff\",\"lessThan\":\"81cc73be40c6f028f1ee3f438ace46afe666dbae\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"drivers/video/fbdev/core/fb_io_fops.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.5\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.5\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.153\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.105\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.46\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.10\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/42a6d8126c194133eafab2b0fd5c8668ebfcba5b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/42bc07b4e5a3c8a02a433388f562a8f46d093e11\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/7110b7b794a2aac2c5cf8eb06ebf2af724c74d50\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/7ff87a01ae3a8cd0208f7499386998223a8b5dba\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/81cc73be40c6f028f1ee3f438ace46afe666dbae\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
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.
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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.
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.
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