Answer in brief
CVE-2026-121996 records a High severity (CVSS 8.2) vulnerability in Gdb: gdbserver: heap disclosure and wild pointer in gdb_parse_agent_expr via untrusted agent-expression length. The current sources do not mark it as known exploited. The current feed maps Red Hat/gcc-toolset-14-gdb (generic), Red Hat/gcc-toolset-15-gdb (generic), Red Hat/gdb (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.2. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Red Hat/gcc-toolset-14-gdb (generic), Red Hat/gcc-toolset-15-gdb (generic), Red Hat/gdb (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Red Hat/gcc-toolset-14-gdbgeneric | * | Not reported |
| Red Hat/gcc-toolset-15-gdbgeneric | * | Not reported |
| Red Hat/gdbgeneric | * | Not reported |
Published upstream
Nov 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Nov 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Nov 5, 2026
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.
Quoted source text, attributed separately from HOL analysis.