CVE-2026-89826 (GCVE-0-2026-89826)

Vulnerability from cvelistv5 – Published: 2026-09-16 10:30 – Updated: 2026-09-16 14:39
VLAI
Title
drm/panthor: harden firmware build-info bounds checks
Summary
In the Linux kernel, the following vulnerability has been resolved: drm/panthor: harden firmware build-info bounds checks panthor_fw_read_build_info() checks whether the metadata range fits in the firmware image with hdr.meta_start + hdr.meta_size. Both fields are u32, so the addition can wrap and let an out-of-bounds range pass validation. The function also reads the "git_sha: " prefix without first checking that the metadata is long enough, and meta_size == 0 can underflow the NULL terminator index. Use subtraction-based bounds checking and reject metadata that is too short to contain the expected prefix and trailing NULL byte.
Severity
7.1 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 2718d91816eeed03c09c8abe872e45f59078768c , < 5516f1acfd07564361cf306cc90a8e513df0f096 (git)
Affected: 2718d91816eeed03c09c8abe872e45f59078768c , < 6ae19dce3e8c13ae73590b3f4311abe9f96bbae8 (git)
Affected: 2718d91816eeed03c09c8abe872e45f59078768c , < 8321b093fa6c297b80586460ce6914d9655df170 (git)
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Linux Linux Affected: 6.10
Unaffected: 0 , < 6.10 (semver)
Unaffected: 6.18.51 , ≤ 6.18.* (semver)
Unaffected: 7.2.5 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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{
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          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/panthor/panthor_fw.c"
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/panthor: harden firmware build-info bounds checks\n\npanthor_fw_read_build_info() checks whether the metadata range fits in the\nfirmware image with hdr.meta_start + hdr.meta_size. Both fields are u32, so\nthe addition can wrap and let an out-of-bounds range pass validation.\n\nThe function also reads the \"git_sha: \" prefix without first checking that\nthe metadata is long enough, and meta_size == 0 can underflow the NULL\nterminator index.\n\nUse subtraction-based bounds checking and reject metadata that is too short\nto contain the expected prefix and trailing NULL byte."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The out-of-bounds reads occur only while panthor_fw_load() parses mali_csffw.bin from the local firmware search path at platform probe (panthor_probe\u2192panthor_fw_init\u2192panthor_fw_load_entry\u2192panthor_fw_read_build_info); no network, DRM ioctl, or /dev/dri/renderD* path supplies attacker-controlled build-info headers.\nAC:L - An attacker fully controls the BUILD_INFO_METADATA u32 meta_start and meta_size fields. Setting both to 0, using meta_size shorter than the git_sha prefix, or wrapping meta_start+meta_size deterministically bypasses the old addition check and performs the OOB memcmp, terminator, and %s reads on every load with no race.\nPR:L - panthor_fw_read_build_info() performs no capability or authentication checks on firmware content; on Mali CSF Android, Chromebook, and embedded deployments the GPU firmware image commonly lives on vendor/firmware partitions writable by local non-root system or vendor service accounts, sufficient to plant the crafted blob before driver probe.\nUI:N - After the malicious mali_csffw.bin is in the firmware search path, panthor_fw_read_build_info() runs automatically during driver probe at boot or bind; no separate victim action such as opening a device node or mounting a filesystem is required.\nS:U - The out-of-bounds kernel reads and any resulting oops remain inside the host kernel that loads the Panthor firmware; this is not a VM escape, IOMMU bypass, or other cross-authority breakout.\nC:H - A wrapping or zero meta_size lets drm_info(\"%s\") walk from the git_sha prefix through kernel memory adjacent to the firmware vmalloc buffer until a NUL, and meta_start==0 with meta_size==0 indexes fw-\u003edata[0xFFFFFFFF]; these are unbounded out-of-bounds reads, not a few-byte leak.\nI:N - panthor_fw_read_build_info() only memcmp()s, indexes, and prints firmware bytes; the wrapping metadata range is never used as a write destination, so there is no out-of-bounds write, use-after-free, or control-flow hijack primitive.\nA:H - Firmware blobs are vmalloc allocations with guard pages, so the 0xFFFFFFFF terminator index (meta_start=meta_size=0) or an unbounded drm_info %s walk past fw-\u003esize readily faults into an unmapped page and oopses or panics the kernel during Mali/Panthor GPU probe."
            }
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        }
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      "providerMetadata": {
        "dateUpdated": "2026-09-16T14:39:04.631Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/8321b093fa6c297b80586460ce6914d9655df170"
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    "datePublished": "2026-09-16T10:30:58.435Z",
    "dateReserved": "2026-09-11T19:38:34.769Z",
    "dateUpdated": "2026-09-16T14:39:04.631Z",
    "state": "PUBLISHED"
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            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/panthor: harden firmware build-info bounds checks\n\npanthor_fw_read_build_info() checks whether the metadata range fits in the\nfirmware image with hdr.meta_start + hdr.meta_size. Both fields are u32, so\nthe addition can wrap and let an out-of-bounds range pass validation.\n\nThe function also reads the \"git_sha: \" prefix without first checking that\nthe metadata is long enough, and meta_size == 0 can underflow the NULL\nterminator index.\n\nUse subtraction-based bounds checking and reject metadata that is too short\nto contain the expected prefix and trailing NULL byte."
          }
        ],
        "id": "CVE-2026-89826",
        "lastModified": "2026-09-16T15:18:11.553",
        "metrics": {
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                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.1,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "NONE",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
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              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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        "vulnStatus": "Received"
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}



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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.

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  • 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.
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Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.