CVE-2026-121994 — Red Hat
HIGHCVE-2026-121994 is a high-severity (CVSS 8.8) CWE-121 vulnerability. The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.
A stack buffer overflow in the GDB client's remote protocol handler allows an attacker-controlled debug target to execute arbitrary code in the GDB process. The vulnerability exists…
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-121994.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Description
A stack buffer overflow in the GDB client's remote protocol handler allows an attacker-controlled debug target to execute arbitrary code in the GDB process. The vulnerability exists in fetch_register_using_p, which decodes a stub's register reply into an alloca-sized buffer without bounding writes by the register width.
Detection & mitigation playbook
VulnerabilityDetect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Remediation status
The records we use list no fixed release for CVE-2026-121994. Check the upstream advisory for a patched version, and apply the exposure-reduction steps below in the meantime.
Mitigate without a patch
Stop feeding it untrusted input: reject or quarantine files and payloads from unverified sources until you can upgrade, restrict accepted formats to the ones you actually need, and run the parsing or decoding step in a least-privileged sandbox or short-lived worker so a crash or corrupted read cannot reach the rest of the process.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This flaw is present in GDB as shipped with Red Hat Enterprise Linux. A developer who connects GDB to a malicious or compromised debug target is exposed to arbitrary code execution in their GDB process.
There is no mitigation for this vulnerability. Users should only connect GDB to trusted debug targets.Source: Red Hat security advisory for CVE-2026-121994 (CC BY 4.0)
Frequently Asked Questions
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