# CVE-2026-12912: libtiff heap overflow in PixarLogDecode with 8BITABGR format

Source: https://junglewise.ai/threats/cve-2026-12912-libtiff-heap-overflow-in-pixarlogdecode-with-8bitabgr-format  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-29. Updated: 2026-06-29  
License: CC BY 4.0 with a link back

CVE-2026-12912 · Severity: high · CVSS 7.3 · Published 2026-06-29

libtiff is a widely used library for reading and writing Tagged Image File Format (TIFF) files, common in professional imaging and document processing. A security flaw allows a specially crafted image to cause a memory overflow when processed by the library. If an application using libtiff opens such a file, it could lead to a system crash or allow an attacker to gain unauthorized control over the application.

Technologies: [Libtiff](https://junglewise.ai/threats/technologies/libtiff). Vendors: [Libtiff](https://junglewise.ai/threats/vendors/libtiff).

## Quick answers

**Is CVE-2026-12912 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-12912 being exploited in the wild.

**How severe is CVE-2026-12912?** High severity, with a CVSS score of 7.3, published 29 June 2026.

**Which products and versions are affected?** Libtiff 4.7.1.

**Is there a fix for CVE-2026-12912?** A patch was published on 2026-04-23: Merge request 873 created to address the issue Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-12912 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2026-12912?** Check whether you run Libtiff at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A heap-based buffer overflow (CWE-122) exists in libtiff's PixarLog codec, specifically within the `horizontalAccumulate8abgr` function and `PixarLogDecode` in `tif_pixarlog.c`. The flaw is triggered when decoding images with `PIXARLOGDATAFMT_8BITABGR` output format and a stride of 3. In this configuration, the decoder writes 4 bytes per 3 decoded samples (adding a synthetic alpha byte) but incorrectly advances the output cursor by only 3 bytes. This pointer mismatch results in a linear overflow of approximately 'width' bytes per scanline. An attacker can exploit this by providing a crafted TIFF image to an application that utilizes these specific libtiff fields, potentially achieving arbitrary code execution. A fix involving corrected pointer advancement and scanline size overrides has been proposed in the libtiff GitLab repository.

## Affected products

- libtiff libtiff 4.7.1
- Red Hat Red Hat Enterprise Linux 7
- Red Hat Red Hat Enterprise Linux 8
- Red Hat Red Hat Enterprise Linux 9
- Red Hat Red Hat Enterprise Linux 10

## Timeline

- 2026-04-23: patched: Merge request 873 created to address the issue
- 2026-06-25: disclosed: Initial report to Red Hat Bugzilla
- 2026-06-29: advisory: CVE published by Red Hat

## References

- [https://access.redhat.com/downloads/content/package-browser/](https://access.redhat.com/downloads/content/package-browser/)
- [https://access.redhat.com/security/cve/CVE-2026-12912](https://access.redhat.com/security/cve/CVE-2026-12912)
- [https://bugzilla.redhat.com/show_bug.cgi?id=2492871](https://bugzilla.redhat.com/show_bug.cgi?id=2492871)
- [https://gitlab.com/libtiff/libtiff/-/merge_requests/873](https://gitlab.com/libtiff/libtiff/-/merge_requests/873)
- [https://gitlab.com/libtiff/libtiff/-/work_items/824](https://gitlab.com/libtiff/libtiff/-/work_items/824)

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