CVE-2026-73556

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5% (41st percentile of EPSS-scored CVEs). 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).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — Patch released this weekElevated
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 5.3Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

vLLM is an inference and serving engine for large language models. Prior to 0.26.0, the structured_outputs.regex parameter in vllm/v1/structured_output/backend_lm_format_enforcer.py is passed to lmformatenforcer.RegexParser without compile_regex_with_timeout or validation in validate_structured_output_request_lm_format_enforcer, allowing an unauthenticated /v1/completions request against the lm-format-enforcer backend to consume a CPU core and stall the structured-output engine path with a catastrophic regular expression. This issue is fixed in version 0.26.0.

CVSS v3
5.3
EG Score
5.3MEDIUMmedium confidence
EG Risk
55
EG Risk 55/100CISA SSVC

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 computed
Severity53% × 45%
Exploitation40% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.5%
EPSS %ILE
42nd
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 13, 2026

Last Modified

September 28, 2026

Advisory Details (4)

Auto-updated Aug 13, 2026
Patch available. Sources: github_commit, github_pr, github_release, github.
githubMentions a patch (unverified)

ReDoS via structured_outputs.regex in the lm-format-enforcer backend (no compile timeout) — missed sibling of GHSA-rwxx-mrjm-wc2m · Advisory · vllm-project/vllm · GitHub

https://github.com/vllm-project/vllm/security/advisories/GHSA-48jh-3gj7-fg8v
github_release Patch Available

v0.26.0

Patch available: vllm-project/vllm v0.26.0

https://github.com/vllm-project/vllm/releases/tag/v0.26.0
github_pr

fix(security): guard lm-format-enforcer regex compile with timeout

Fix merged in vllm-project/vllm PR #47595 on 2026-07-14 — awaiting tagged release

https://github.com/vllm-project/vllm/pull/47595
github_commit

commit c9a788eedc41 (vllm-project/vllm)

Fix landed in vllm-project/vllm commit c9a788eedc41 — awaiting tagged release

https://github.com/vllm-project/vllm/commit/c9a788eedc412acceaa5112e0d44624b49841577

Vendor Advisories for CVE-2026-73556(14)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(13)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatrhelai3/disk-image-cuda-rhel9:17909574172026-10-05redhat
redhatrhelai3/bootc-rocm-rhel9:17906144472026-10-05redhat
redhatrhelai3/disk-image-cuda-rhel9:17909541792026-10-05redhat
redhatrhelai3/bootc-gcp-cuda-rhel9:17909363342026-10-05redhat
redhatrhaii/vllm-cpu-rhel9:17900757932026-09-23redhat
redhatrhaii/vllm-cuda-rhel9:17900901312026-09-23redhat
redhatrhaii/vllm-spyre-rhel9:17900761412026-09-23redhat
redhatrhaii/vllm-rocm-rhel9:17901096202026-09-23redhat
redhatrhaii/vllm-spyre-rhel9:17896812012026-09-21redhat
redhatrhaii/vllm-cpu-rhel9:17896811282026-09-21redhat
redhatrhaii/vllm-cuda-rhel9:17896811262026-09-21redhat
redhatrhaii/vllm-rocm-rhel9:17896811262026-09-21redhat
redhatrhaiis/vllm-cuda-rhel9:17895827762026-09-17redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
vllm0.0.1 ... 0.9.2 (92 versions)
  • every version up to 0.26.0: fixed in 0.26.0
—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 52× 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.

Showing the most recent 100 of 107 total refreshes for this CVE.

  1. 2026-10-09 20:07 UTCEPSS rescore
  2. 2026-10-08 17:13 UTCEPSS rescore
  3. 2026-10-07 23:48 UTCEPSS rescore
  4. 2026-10-06 15:18 UTCEPSS rescore
  5. 2026-10-06 13:22 UTCEG score recompute
  6. 2026-10-06 13:22 UTCVendor advisory
  7. 2026-10-05 17:43 UTCEPSS rescore
  8. 2026-10-04 23:22 UTCEPSS rescore
  9. 2026-10-04 22:19 UTCVendor advisory
  10. 2026-10-03 19:49 UTCEG score recompute
  11. 2026-10-03 19:49 UTCVendor advisory
  12. 2026-10-03 14:26 UTCEPSS rescore
  13. 2026-10-02 07:33 UTCEG score recompute
  14. 2026-10-02 07:33 UTCVendor advisory
  15. 2026-10-01 19:50 UTCEPSS rescore
  16. 2026-09-30 21:47 UTCEG score recompute
  17. 2026-09-30 21:47 UTCVendor advisory
  18. 2026-09-29 15:24 UTCEPSS rescore
  19. 2026-09-28 18:56 UTCEG score recompute
  20. 2026-09-28 18:56 UTCVendor advisory
  21. 2026-09-28 13:52 UTCEPSS rescore
  22. 2026-09-28 09:28 UTCEG score recompute
  23. 2026-09-28 09:28 UTCVendor advisory
  24. 2026-09-27 13:48 UTCEPSS rescore
  25. 2026-09-27 09:44 UTCEG score recompute
Show 75 more
  1. 2026-09-27 09:44 UTCVendor advisory
  2. 2026-09-26 15:59 UTCEPSS rescore
  3. 2026-09-25 03:33 UTCEG score recompute
  4. 2026-09-25 03:33 UTCVendor advisory
  5. 2026-09-23 23:33 UTCVendor advisory
  6. 2026-09-22 23:49 UTCEG score recompute
  7. 2026-09-22 23:49 UTCVendor advisory
  8. 2026-09-21 23:54 UTCEG score recompute
  9. 2026-09-21 23:54 UTCVendor advisory
  10. 2026-09-21 21:09 UTCEPSS rescore
  11. 2026-09-21 00:09 UTCEG score recompute
  12. 2026-09-20 20:16 UTCEPSS rescore
  13. 2026-09-19 23:58 UTCEG score recompute
  14. 2026-09-19 00:14 UTCEG score recompute
  15. 2026-09-18 19:28 UTCEPSS rescore
  16. 2026-09-18 00:29 UTCEG score recompute
  17. 2026-09-16 23:59 UTCEG score recompute
  18. 2026-09-16 14:08 UTCEPSS rescore
  19. 2026-09-16 05:15 UTCEPSS rescore
  20. 2026-09-15 21:55 UTCEG score recompute
  21. 2026-09-15 03:12 UTCEPSS rescore
  22. 2026-09-13 20:28 UTCEG score recompute
  23. 2026-09-12 20:43 UTCEG score recompute
  24. 2026-09-12 15:02 UTCEPSS rescore
  25. 2026-09-11 20:58 UTCEG score recompute
  26. 2026-09-11 14:53 UTCEPSS rescore
  27. 2026-09-10 21:13 UTCEG score recompute
  28. 2026-09-10 09:35 UTCEPSS rescore
  29. 2026-09-09 06:44 UTCEG score recompute
  30. 2026-09-08 22:01 UTCEPSS rescore
  31. 2026-09-08 06:58 UTCEG score recompute
  32. 2026-09-07 07:13 UTCEG score recompute
  33. 2026-09-06 13:48 UTCEPSS rescore
  34. 2026-09-06 07:22 UTCEG score recompute
  35. 2026-09-05 07:37 UTCEG score recompute
  36. 2026-09-04 07:52 UTCEG score recompute
  37. 2026-09-04 05:07 UTCEPSS rescore
  38. 2026-09-03 06:58 UTCEG score recompute
  39. 2026-09-02 14:12 UTCEPSS rescore
  40. 2026-09-02 07:08 UTCEG score recompute
  41. 2026-09-01 13:54 UTCEPSS rescore
  42. 2026-09-01 07:18 UTCEG score recompute
  43. 2026-09-01 04:40 UTCEPSS rescore
  44. 2026-09-01 04:40 UTCEPSS rescore
  45. 2026-08-31 07:31 UTCEG score recompute
  46. 2026-08-30 19:18 UTCEPSS rescore
  47. 2026-08-30 19:17 UTCEPSS rescore
  48. 2026-08-30 07:25 UTCEG score recompute
  49. 2026-08-30 01:22 UTCEPSS rescore
  50. 2026-08-29 07:37 UTCEG score recompute
  51. 2026-08-28 21:42 UTCEPSS rescore
  52. 2026-08-27 19:32 UTCEG score recompute
  53. 2026-08-27 14:25 UTCEPSS rescore
  54. 2026-08-26 18:43 UTCEG score recompute
  55. 2026-08-26 14:47 UTCEPSS rescore
  56. 2026-08-25 17:12 UTCEG score recompute
  57. 2026-08-25 13:49 UTCEPSS rescore
  58. 2026-08-24 17:14 UTCEG score recompute
  59. 2026-08-23 17:27 UTCEG score recompute
  60. 2026-08-23 00:19 UTCEPSS rescore
  61. 2026-08-22 17:43 UTCEG score recompute
  62. 2026-08-21 23:49 UTCEPSS rescore
  63. 2026-08-21 17:57 UTCEG score recompute
  64. 2026-08-20 22:56 UTCEPSS rescore
  65. 2026-08-19 18:27 UTCEG score recompute
  66. 2026-08-19 17:04 UTCEPSS rescore
  67. 2026-08-18 17:06 UTCEG score recompute
  68. 2026-08-18 13:49 UTCEPSS rescore
  69. 2026-08-18 13:49 UTCEPSS rescore
  70. 2026-08-17 16:47 UTCEG score recompute
  71. 2026-08-17 13:47 UTCEPSS rescore
  72. 2026-08-16 17:03 UTCEG score recompute
  73. 2026-08-16 14:56 UTCEPSS rescore
  74. 2026-08-16 14:56 UTCEPSS rescore
  75. 2026-08-16 02:15 UTCEPSS rescore

Related CVEs(same product + same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-73556?
CVE-2026-73556 is a medium vulnerability published on August 13, 2026. vLLM is an inference and serving engine for large language models. Prior to 0.26.0, the structuredoutputs.regex parameter in vllm/v1/structuredoutput/backendlmformatenforcer.py is passed to lmformatenforcer.RegexParser without compileregexwithtimeout or validation in…
When was CVE-2026-73556 disclosed?
CVE-2026-73556 was first published on August 13, 2026, with the most recent update on September 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-73556 actively exploited?
CVE-2026-73556 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (42nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-73556?
CVE-2026-73556 has a CVSS base score of 5.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-73556?
A fix for CVE-2026-73556 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-73556 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-73556

Explore →

Is Your Infrastructure Affected by CVE-2026-73556?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs