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Fencer Vulns
high 8.1

CVE-2026-121997 json

Gdb: gdbserver: heap buffer overflow in cmd_qtdpsrc via qtdpsrc declared/actual length mismatch

published 2026-11-05 3 d ago modified 2026-11-06 2 d ago also EUVD-2026-117574

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 53%
public exploits
0
none known

Summary

A heap buffer overflow in gdbserver's QTDPsrc packet handler allows an unauthenticated remote attacker to achieve native code execution in the gdbserver process. The vulnerability results from a mismatch between a packet's declared source length and the actual data length, causing hex2bin to write beyond the allocated heap buffer.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-121997 updated cvss 8.1

gdb: gdbserver: heap buffer overflow in cmd_qtdpsrc via QTDPsrc declared/actual length mismatch

  • Red Hat Enterprise Linux 6 gdb, gdb-gdbserver, gdb 17.2-4.el10_3 Red Hat Enterprise Linux 7 gdb-gdbserver, gdb 17.2-4.el10_3 Red Hat Enterprise Linux 8 gdb, gdb-headless, gdb-gdbserver, gdb 17.2-4.el10_3, gcc-toolset-14-gdb 14.2-3.el8_10, gcc-toolset-15-gdb 16.3-1.el8_10 Red Hat Enterprise Linux 9 gdb, gdb-minimal, gdb-headless, gdb-gdbserver, gdb 17.2-4.el10_3 Red Hat Enterprise Linux 10 gdb 17.2-4.el10_3 Red Hat Hardened Images gdb 17.2-4.el10_3
    affected: workaround, no fix available
  • Red Hat Enterprise Linux 8 crash 8.0.6-1.el10 Red Hat Enterprise Linux 9 crash 8.0.6-1.el10 Red Hat Enterprise Linux 10 crash 8.0.6-1.el10
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
4 d ago

Exploit prediction

0.71% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 6
  • 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 Hardened Images

Classification

Weakness
  • CWE-122 Heap-based Buffer Overflow

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.