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CVE-2026-8669 TONYC CVE debrief

Imager for Perl versions through 1.030 contain a heap out-of-bounds write vulnerability in multi-frame GIF processing. The flaw exists in `Imager::File::GIF`'s `i_readgif_multi_low` function, which allocates a single row buffer (`GifRow`) sized to the GIF's global screen width (`SWidth`) and reuses it across all images in the file. While the page-match branch validates `Image.Width + Image.Left > SWidth` before `DGifGetLine` writes, the skip-image branch at `imgif.c:790-805` invokes `DGifGetLine(GifFile, GifRow, Width)` without this bounds check, permitting heap corruption when processing crafted multi-frame GIF files.

Vendor
TONYC
Product
Imager
CVSS
MEDIUM 6.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-15
Original CVE updated
2026-05-18
Advisory published
2026-05-15
Advisory updated
2026-05-18

Who should care

Organizations running Perl applications that process user-supplied or untrusted GIF images through the Imager library, particularly those handling multi-frame GIFs in web applications, content management systems, or automated image processing pipelines.

Technical summary

The vulnerability stems from inconsistent bounds validation between two code paths in `imgif.c`. The page-match branch correctly validates image dimensions against the global screen width before writing to the reused row buffer, but the skip-image branch (lines 790-805) calls `DGifGetLine` with the image's `Width` parameter directly without verifying it fits within the allocated `GifRow` buffer sized to `SWidth`. This allows a crafted multi-frame GIF with frame dimensions exceeding the global screen width to trigger a heap buffer overflow during the skip-image processing path. The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N) indicates network attack vector with low complexity, no privileges required, and no user interaction, with limited confidentiality and integrity impact.

Defensive priority

medium

Recommended defensive actions

  • Upgrade Imager to version 1.031 or later, which contains the security fix
  • Review applications processing untrusted GIF files via Imager::File::GIF for potential exposure
  • Monitor Perl application logs for anomalous GIF processing failures that may indicate exploitation attempts
  • Validate GIF file sources where possible before processing through Imager
  • Apply principle of least privilege to Perl processes handling image conversion operations

Evidence notes

Vulnerability description sourced from NVD record published 2026-05-15 and modified 2026-05-18. Technical details reference specific source file (`imgif.c`) and line range (790-805). Patch commit identified in source references. Vendor attribution to TONYC (Perl module maintainer) derived from MetacPAN reference with low confidence per source metadata.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-8669 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-8669

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-8669 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-8669

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Source reference

    Unverified legacy reference

    URL: https://github.com/tonycoz/imager/commit/782e9c06cc75a0f7eed383f39522f51f44598b04.patch

    9b29abf9-4ab0-4765-b253-1875cd9b441e

  • Source reference

    Unverified legacy reference

    URL: https://metacpan.org/release/TONYC/Imager-1.031/source/Changes

    9b29abf9-4ab0-4765-b253-1875cd9b441e

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.