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VulnerabilityPublished Updated

CVE-2026-27168: HappySeaFox sail · Heap-based Buffer Overflow

Affects HappySeaFox sailSource CVE Database V5

0

Not known to be exploited · CVSS 8.8 High.

Data as of 26 Oct 2026, 09:16 UTC

CVSS 3.1 base score
8.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 37% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 20 Feb 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
HappySeaFoxsailAffected
  • <=0.9.10
Fixed in–

AI-suggested

Given the absence of an official patch, organizations should implement several practical mitigations: 1) Immediately audit and inventory all systems and applications using the HappySeaFox sail library, focusing on versions up to 0.9.10. 2) Avoid processing or accepting XWD image files from untrusted or unauthenticated sources. 3) Implement network-level controls to block or monitor traffic containing XWD files, especially in environments where image uploads are allowed. 4) Employ application-layer input validation to check the bytes_per_line value before processing, if possible, by modifying the source code or applying temporary patches to enforce size checks against buffer allocations. 5) Use sandboxing or containerization to isolate applications that process images, limiting the impact of potential exploitation. 6) Monitor logs and system behavior for signs of heap corruption or crashes related to image processing. 7) Stay alert for vendor updates or community patches and plan for rapid deployment once a fix becomes available. 8) Consider alternative image processing libraries that do not exhibit this vulnerability if immediate patching is not feasible.

Description

SAIL is a cross-platform library for loading and saving images with support for animation, metadata, and ICC profiles. All versions are vulnerable to Heap-based Buffer Overflow through the XWD parser's use of the bytes_per_line value. The value os read directly from the file as the read size in io->strict_read(), and is never compared to the actual size of the destination buffer. An attacker can provide an XWD file with an arbitrarily large bytes_per_line, causing a massive write operation beyond the buffer heap allocated for the image pixels. The issue did not have a fix at the time of publication.

References

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