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No exploitation reportedAwaiting NVD analysis

CVE-2026-121996

Gdb: gdbserver: heap disclosure and wild pointer in gdb_parse_agent_expr via untrusted agent-expression length

No exploitation reported by the sources we read.

  • Published2026-11-05
  • WeaknessCWE-822

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A length validation flaw in gdbserver's agent-expression parser allows an unauthenticated remote attacker to read uninitialized heap memory from the gdbserver process and cause a denial of service. Disclosed heap content includes addresses suitable for defeating ASLR in further exploitation.

Timeline

dates in UTC
  1. 2026-11-0516:08CVE publishedCNA

Versions per branch

Products declared by the CNA

As redhat, the CNA that assigned this CVE, declared them in the CVE record; versions as written. NVD lists no product for this CVE yet: this is the only product data so far.

5 more products in the CVE record.

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-11-05

Neither OSV.dev nor the vendor advisories we read list affected versions for CVE-2026-121996 yet.

Full record on NVD

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Metasploit modules
none listed
Metasploit Framework

Sources

  • CNACVSS 3.18.22026-11-05
  • NVDCVSS 3.18.2read 2026-11-05
  • CNAweakness (CWE)CWE-8222026-11-05
  • NVDweakness (CWE)CWE-822read 2026-11-05

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
Published
2026-11-05
Last Modified
2026-11-05
NVD status
Awaiting Analysis

Frequently asked questions

What is CVE-2026-121996?

A length validation flaw in gdbserver's agent-expression parser allows an unauthenticated remote attacker to read uninitialized heap memory from the gdbserver process and cause a denial of service. Disclosed heap content includes addresses suitable for defeating ASLR in further exploitation.

Is CVE-2026-121996 actively exploited?

Active exploitation of CVE-2026-121996 has not been confirmed.

What is the CVSS score for CVE-2026-121996?

CVE-2026-121996 has a CVSS v3 base score of 8.2 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H.

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