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PatchSiren cyber security CVE debrief

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.

Official resources

2026-05-15