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CVE-2026-12891

MEDIUM 4.3

Published 2026-06-23 · Last modified 2026-06-24

A flaw was found in the GStreamer gst-plugins-bad package. When processing a malformed H.266/VVC video stream with a crafted aspect ratio indicator value, the H.266 parser performs an out-of-bounds read of up to 8 bytes from adjacent memory. This flaw allows an attacker to craft a malicious H.266 video file or stream that, when processed by a GStreamer-based application, could leak limited memory contents through video metadata, potentially exposing sensitive information from the application's address space.

NO EXPLOITATION SIGNALS

No known exploitation, public exploit, or elevated probability at this time. Track for changes.

Exploitation likelihood

0.3%chance of exploitation in 30 days · 20th percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

4.3CVSS 3.1 · MEDIUM

  • ConfidentialityLow
  • IntegrityNone
  • AvailabilityNone

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ⚠User interaction: A user must take an action (click / open a file)
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-12891/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-12891/poc.json

Affected

Vendors Red Hat Gstreamer Redhat

Products Red Hat Enterprise Linux 10 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 9 Gstreamer Enterprise Linux

Weakness (CWE)

  • CWE-125: Out-of-bounds Read

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

Known Affected Software Configurations

VendorProductVersion range
GstreamerGstreamer*
RedhatEnterprise Linux8.0
RedhatEnterprise Linux9.0
RedhatEnterprise Linux10.0

All CVSS metrics

  • MEDIUM 4.3 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
  • MEDIUM 4.3 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

References

Advisories

Technical & other

Sources: NVD · CVE.org · EPSS