Vulnerability · Published Nov 5, 2026 · Assigned by redhat
CVE-2026-121994Gdb: gdb: stack buffer overflow in fetch_register_using_p via unchecked p-reply length
High 8.8
In plain English
A high-severity stack buffer overflow in Red Hat Enterprise Linux 10 from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities).
Severity (CVSS 3.1)8.8High
Exploit odds (30 days)0.5%top 58.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | gdb | no fix listed | DEBIAN-CVE-2026-121994 |
| Debian:13 | gdb | no fix listed | DEBIAN-CVE-2026-121994 |
| Debian:14 | gdb | no fix listed | DEBIAN-CVE-2026-121994 |
| Ubuntu:22.04:LTS | gdb | no fix listed | UBUNTU-CVE-2026-121994 |
| Ubuntu:24.04:LTS | gdb | no fix listed | UBUNTU-CVE-2026-121994 |
| Ubuntu:26.04:LTS | gdb | no fix listed | UBUNTU-CVE-2026-121994 |
| Ubuntu:26.10 | gdb | no fix listed | UBUNTU-CVE-2026-121994 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | see references |
| Red Hat | Red Hat Enterprise Linux 10 | see references |
| Red Hat | Red Hat Enterprise Linux 6 | see references |
| Red Hat | Red Hat Enterprise Linux 7 | see references |
| Red Hat | Red Hat Enterprise Linux 8 | see references |
| Red Hat | Red Hat Enterprise Linux 8 | see references |
| Red Hat | Red Hat Enterprise Linux 8 | see references |
| Red Hat | Red Hat Enterprise Linux 8 | see references |
| Red Hat | Red Hat Enterprise Linux 9 | see references |
| Red Hat | Red Hat Enterprise Linux 9 | see references |
| Red Hat | Red Hat Hardened Images | see references |
Weakness: CWE-121 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
References
- https://access.redhat.com/security/cve/CVE-2026-121994 vdb-entry, x_refsource_REDHAT
- RHBZ#2565676 issue-tracking, x_refsource_REDHAT