CVE-2026-73559

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 68% 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).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

vLLM is an inference and serving engine for large language models. From 0.19.0 until 0.26.0, the /v1/completions CompletionRequest.prompt field in vllm/entrypoints/openai/completion/protocol.py accepts an unbounded list[str] or list[list[int]], prompt_to_seq() in vllm/renderers/inputs/preprocess.py and OnlineRenderer.preprocess_completion() in vllm/renderers/online_renderer.py expand every element, and vllm/entrypoints/openai/completion/serving.py creates one engine generator and response slot per prompt, allowing an authenticated API client to exhaust CPU, memory, async scheduling capacity, engine request slots, and response buffering with one request. This issue is fixed in version 0.26.0.

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
45(Track)
EG Risk 45/100SSVC: 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 computed
Severity65% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
32%
KEV
Not listed

Published

August 13, 2026

Last Modified

August 14, 2026

Advisory Details (4)

Auto-updated Aug 13, 2026
Patch available. Sources: github_commit, github_release, github, github_pr.
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_commit

commit 675f4295cdfe (vllm-project/vllm)

Fix landed in vllm-project/vllm commit 675f4295cdfe — awaiting tagged release

https://github.com/vllm-project/vllm/commit/675f4295cdfe0d870471c2b51bfeca3a68a9569e
github_pr

fix(security): bound completion prompt list to prevent unbounded engine fan-out

Fix merged in vllm-project/vllm PR #47845 on 2026-07-07 — awaiting tagged release

https://github.com/vllm-project/vllm/pull/47845
github Patch Available

Completion prompt lists fan out into unbounded engine requests · Advisory · vllm-project/vllm · GitHub

https://github.com/vllm-project/vllm/security/advisories/GHSA-87x5-vmc3-756j

Vendor Advisories for CVE-2026-73559(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)
PackageVulnerable rangeFixed inDependents
vllm0.19.0 ... 0.25.1 (12 versions)0.26.0—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 18× in last 7d / 21× 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.

  1. 2026-08-21 02:44 UTCEG score recompute
  2. 2026-08-20 22:56 UTCEPSS rescore
  3. 2026-08-20 04:52 UTCEG score recompute
  4. 2026-08-19 17:04 UTCEPSS rescore
  5. 2026-08-19 06:59 UTCEG score recompute
  6. 2026-08-18 13:49 UTCEPSS rescore
  7. 2026-08-18 13:49 UTCEPSS rescore
  8. 2026-08-18 09:06 UTCEG score recompute
  9. 2026-08-17 13:47 UTCEPSS rescore
  10. 2026-08-17 11:10 UTCEG score recompute
  11. 2026-08-16 14:56 UTCEPSS rescore
  12. 2026-08-16 14:56 UTCEPSS rescore
  13. 2026-08-16 13:18 UTCEG score recompute
  14. 2026-08-16 02:15 UTCEPSS rescore
  15. 2026-08-15 15:26 UTCEG score recompute
  16. 2026-08-15 01:31 UTCEPSS rescore
  17. 2026-08-14 17:34 UTCEG score recompute
  18. 2026-08-14 17:07 UTCEG score recompute
  19. 2026-08-13 16:25 UTCEG score recompute
  20. 2026-08-13 15:32 UTCEG score recompute
  21. 2026-08-13 15:31 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-73559?
CVE-2026-73559 is a medium vulnerability published on August 13, 2026. vLLM is an inference and serving engine for large language models. From 0.19.0 until 0.26.0, the /v1/completions CompletionRequest.prompt field in vllm/entrypoints/openai/completion/protocol.py accepts an unbounded list[str] or list[list[int]], prompttoseq() in vllm/renderers/inputs/preprocess.py…
When was CVE-2026-73559 disclosed?
CVE-2026-73559 was first published in the National Vulnerability Database on August 13, 2026, with the most recent update on August 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-73559 actively exploited?
CVE-2026-73559 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 67.7% of all scored CVEs.
What is the CVSS score of CVE-2026-73559?
CVE-2026-73559 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-73559?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-73559, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-73559

Explore →

Is Your Infrastructure Affected by CVE-2026-73559?

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

Start Free Scan →Browse All CVEs