vLLM is a high-throughput and memory-efficient inference and serving engine for LLMs. Prior to 0.24.0, the structured_outputs.regex API parameter passes a user-supplied regular expression string directly to the grammar compiler backends with no compilation timeout; in the xgrammar backend the string reaches the regex compiler with no guard, and in the outlines backend the validation step blocks structural issues such as lookarounds and backreferences but performs no complexity analysis, so a pattern with nested quantifiers passes all checks and causes exponential state-space expansion, allowing a single request containing an adversarial regex to hang an inference worker indefinitely and deny service. This issue is fixed in version 0.24.0.
CVE-2026-55574
This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 75% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- High severity, but no confirmed exploitation yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 7.5
- EG Score
- 7.5(medium)
- EG Risk
- 34(Track)EG Risk 34/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity75% × 45%Exploitation0% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS
- 24.8%
- KEV
- Not listed
Published
July 6, 2026
Last Modified
July 7, 2026
Advisory Details (3)
Auto-updated Jul 6, 2026ReDoS via structured_outputs.regex compiled without timeout in xgrammar and outlines backends · Advisory · vllm-project/vllm · GitHub
https://github.com/vllm-project/vllm/security/advisories/GHSA-rwxx-mrjm-wc2m[Security] Add timeout guard for regex compilation in structured outp…
Fix merged in vllm-project/vllm PR #45118 on 2026-06-13 — awaiting tagged release
https://github.com/vllm-project/vllm/pull/45118commit 2b3006076c5e (vllm-project/vllm)
Fix landed in vllm-project/vllm commit 2b3006076c5e — awaiting tagged release
https://github.com/vllm-project/vllm/commit/2b3006076c5e9bc4cda9e03e3641388de3c5c286Vendor Advisories for CVE-2026-55574(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(1 across 1 ecosystem)
PyPI(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| vllm | 0.0.1 ... 0.9.2 (89 versions) | 0.24.0 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 8× in last 7d / 28× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-23 03:20 UTCEG score recompute
- 2026-07-22 14:08 UTCEPSS rescore
- 2026-07-20 17:08 UTCEPSS rescore
- 2026-07-19 14:31 UTCEPSS rescore
- 2026-07-19 14:31 UTCEPSS rescore
- 2026-07-19 02:29 UTCEPSS rescore
- 2026-07-18 10:04 UTCEPSS rescore
- 2026-07-16 17:03 UTCEPSS rescore
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 02:00 UTCEPSS rescore
- 2026-07-15 02:00 UTCEPSS rescore
- 2026-07-13 22:31 UTCEPSS rescore
- 2026-07-13 06:13 UTCEPSS rescore
- 2026-07-13 06:13 UTCEPSS rescore
- 2026-07-12 05:46 UTCEPSS rescore
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-08 15:16 UTCEPSS rescore
- 2026-07-08 15:16 UTCEPSS rescore
- 2026-07-08 07:39 UTCEG score recompute▼ 1.20
- 2026-07-07 20:14 UTCNVD updateCVSS v3 → 7.5
- 2026-07-07 13:46 UTCEPSS rescore
Show 3 moreShow fewer
- 2026-07-07 13:46 UTCEPSS rescore
- 2026-07-06 20:30 UTCEG score recompute
- 2026-07-06 20:29 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-55574?
When was CVE-2026-55574 disclosed?
Is CVE-2026-55574 actively exploited?
What is the CVSS score of CVE-2026-55574?
How do I remediate CVE-2026-55574?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-55574
Is Your Infrastructure Affected by CVE-2026-55574?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.