{"id":"CVE-2026-121996","title":"Gdb: gdbserver: heap disclosure and wild pointer in gdb_parse_agent_expr via untrusted agent-expression length","summary":"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 address…","severity":"high","cvss":8.2,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","cvssSource":"cna","cwe":["CWE-822"],"vendor":"Red Hat","product":"crash","affected":["crash","gdb (all versions)","gdb (all versions)","gdb (all versions)","crash","gcc-toolset-14-gdb (all versions)","gcc-toolset-15-gdb (all versions)","gdb (all versions)","crash","gdb (all versions)","gdb (all versions)"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-11-05T18:52:10.802560Z"},"published":"2026-11-05","updated":"2026-11-05","sourceUpdated":"2026-11-05T18:52:23.924Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-121996","references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-121996"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2565678","label":"RHBZ#2565678"}],"tags":["cve.org"],"ingestedAt":"2026-11-05T22:38:31.482Z","slug":"CVE-2026-121996","body":"## Overview\n\nA 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.\n\n## Affected\n\n- `crash`\n- `gdb (all versions)`\n- `gdb (all versions)`\n- `gdb (all versions)`\n- `crash`\n- `gcc-toolset-14-gdb (all versions)`\n- `gcc-toolset-15-gdb (all versions)`\n- `gdb (all versions)`\n- `crash`\n- `gdb (all versions)`\n- `gdb (all versions)`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n### Workarounds\n\nThere is no mitigation for this vulnerability. gdbserver has no authentication mechanism; exposure is limited only by network access to the gdbserver port.","depth":"twilight","depthScore":45,"depthScoreParts":{"impact":45.1,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}