CVE-2026-73556

MEDIUMPre-NVD 5.35.3
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 5.3 from GitHub Security Advisory (severity: MODERATE) published 2026-09-04. A secondary CVSS source baseline 5.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Elevated

Also known asEUVD-2026-58063 (ENISA EUVD) · GHSA-48jh-3gj7-fg8v (GitHub Security Advisories) · PYSEC-2026-3933 (OSV.dev)Source: ENISA EUVD

5.3EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 5.3Exploit: No code on recordExposed 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 55/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity53% × 45%
Impact severity (EG Severity): CVSS 5.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
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
44th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (5.3): severity, escalated by confirmed exploitation. This CVE's 5.3 is its impact severity (EG Severity), not escalated.

EG Severity
5.3 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-31). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track 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). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

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.
GitHub advisoryMentions 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 pull request

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

Patch Availability(20)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatrhoai/odh-kserve-storage-initializer-rhel9:17909585492026-10-19redhat
redhatrhaii/vllm-cpu-rhel9:17914736142026-10-13redhat
redhatrhaii/vllm-rocm-rhel9:17914258692026-10-13redhat
redhatrhaii/vllm-spyre-rhel9:17918183572026-10-13redhat
redhatrhaii/vllm-gaudi-rhel9:17914271822026-10-13redhat
redhatrhaii/vllm-cuda-rhel9:17914736312026-10-13redhat
redhatrhelai3/bootc-rocm-rhel9:17906144472026-10-05redhat
redhatrhelai3/disk-image-cuda-rhel9:17909574172026-10-05redhat
redhatrhelai3/disk-image-cuda-rhel9:17909541792026-10-05redhat
redhatrhelai3/bootc-gcp-cuda-rhel9:17909363342026-10-05redhat
redhatrhaii/vllm-cuda-rhel9:17900901312026-09-23redhat
redhatrhaii/vllm-cpu-rhel9:17900757932026-09-23redhat
redhatrhaii/vllm-rocm-rhel9:17901096202026-09-23redhat
redhatrhaii/vllm-spyre-rhel9:17900761412026-09-23redhat
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
pipvllm @ 0.26.0 (fixes < 0.26.0)—ghsa

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.

Additional Vendor Advisories

(6)

Data Freshness Timeline

(refreshed 7× in last 7d / 33× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed its CVE.org record (CNA or CISA ADP). An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 153 rows on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 53 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-13 16:57 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  2. 2026-11-12 16:34 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  3. 2026-11-11 16:40 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  4. 2026-11-10 16:45 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  5. 2026-11-09 16:36 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  6. 2026-11-08 16:40 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  7. 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  8. 2026-11-06 16:39 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  9. 2026-11-05 16:38 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  10. 2026-11-04 16:36 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  11. 2026-11-03 16:49 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  12. 2026-11-02 16:46 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  13. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  14. 2026-11-01 07:39 UTCGHSA enrichmentGHSA-48jh-3gj7-fg8v · GitHub severity MODERATE · GitHub CVSS 5.3
  15. 2026-11-01 07:39 UTCEchelonGraph re-scored
  16. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  17. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  18. 2026-10-30 06:55 UTCOSV refresh
  19. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  20. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  21. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  22. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  23. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  24. 2026-10-25 14:05 UTCEchelonGraph re-scored
  25. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
Show 75 more
  1. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  2. 2026-10-22 19:02 UTCEchelonGraph re-scored
  3. 2026-10-22 19:02 UTCVendor advisory
  4. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  5. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  6. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  7. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  8. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  9. 2026-10-18 03:15 UTCEchelonGraph re-scored
  10. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  11. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  12. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  13. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  14. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  15. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  16. 2026-10-12 15:40 UTCEchelonGraph re-scored
  17. 2026-10-11 19:26 UTCEchelonGraph re-scored
  18. 2026-10-11 16:42 UTCEchelonGraph re-scored
  19. 2026-10-11 14:01 UTCEchelonGraph re-scored
  20. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  21. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  22. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  23. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  24. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  25. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  26. 2026-10-06 13:22 UTCEchelonGraph re-scored
  27. 2026-10-06 13:22 UTCVendor advisory
  28. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  29. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  30. 2026-10-04 22:19 UTCVendor advisory
  31. 2026-10-03 19:49 UTCEchelonGraph re-scored
  32. 2026-10-03 19:49 UTCVendor advisory
  33. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  34. 2026-10-02 07:33 UTCEchelonGraph re-scored
  35. 2026-10-02 07:33 UTCVendor advisory
  36. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  37. 2026-09-30 21:47 UTCEchelonGraph re-scored
  38. 2026-09-30 21:47 UTCVendor advisory
  39. 2026-09-29 15:24 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  40. 2026-09-28 18:56 UTCEchelonGraph re-scored
  41. 2026-09-28 18:56 UTCVendor advisory
  42. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  43. 2026-09-28 09:28 UTCEchelonGraph re-scored
  44. 2026-09-28 09:28 UTCVendor advisory
  45. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  46. 2026-09-27 09:44 UTCEchelonGraph re-scored
  47. 2026-09-27 09:44 UTCVendor advisory
  48. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  49. 2026-09-25 03:33 UTCEchelonGraph re-scored
  50. 2026-09-25 03:33 UTCVendor advisory
  51. 2026-09-23 23:33 UTCVendor advisory
  52. 2026-09-22 23:49 UTCEchelonGraph re-scored
  53. 2026-09-22 23:49 UTCVendor advisory
  54. 2026-09-21 23:54 UTCEchelonGraph re-scored
  55. 2026-09-21 23:54 UTCVendor advisory
  56. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  57. 2026-09-21 00:09 UTCEchelonGraph re-scored
  58. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  59. 2026-09-19 23:58 UTCEchelonGraph re-scored
  60. 2026-09-19 00:14 UTCEchelonGraph re-scored
  61. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  62. 2026-09-18 00:29 UTCEchelonGraph re-scored
  63. 2026-09-16 23:59 UTCEchelonGraph re-scored
  64. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  65. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  66. 2026-09-15 21:55 UTCEchelonGraph re-scored
  67. 2026-09-15 03:12 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  68. 2026-09-13 20:28 UTCEchelonGraph re-scored
  69. 2026-09-12 20:43 UTCEchelonGraph re-scored
  70. 2026-09-12 15:02 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  71. 2026-09-11 20:58 UTCEchelonGraph re-scored
  72. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  73. 2026-09-10 21:13 UTCEchelonGraph re-scored
  74. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  75. 2026-09-09 06:44 UTCEchelonGraph re-scored

Frequently asked(5)

What is CVE-2026-73556?
CVE-2026-73556 is a medium-severity vulnerability; its CVE record was published on August 13, 2026. 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…
When was the CVE record for CVE-2026-73556 published?
The CVE record for CVE-2026-73556 was published on August 13, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 28, 2026; the record at its source may have been updated since.
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 (44th 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

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