CVE-2026-90878

MEDIUMPre-NVD 4.34.3—
EchelonGraph scoreHIGH confidence

Score 4.3 from GitHub Security Advisory (severity: LOW) published 2026-09-15. a secondary CVSS source baseline 4.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 5 sources updated this weekElevated
4.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.3Exploit: Elevated riskExposed: 0

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

A vulnerability was determined in vllm-project vLLM up to 0.27.1. This affects an unknown part of the file /v1/chat/completions of the component Jinja Template Rendering. This manipulation of the argument chat_template causes resource consumption. The attack can be initiated remotely. The exploit has been publicly disclosed and may be utilized. The pull request to fix this issue awaits acceptance.

CVSS v3
4.3
EG Score
4.3(high)
EG Risk
35(Track)
EG Risk 35/100SSVC: 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
Severity43% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
23%
KEV
Not listed

Published

September 15, 2026

Last Modified

September 15, 2026

Advisory Details (3)

Auto-updated Sep 15, 2026
No patch confirmed yet. Sources: github_pr.
generic

GitHub - vllm-project/vllm: A high-throughput and memory-efficient inference and serving engine for LLMs · GitHub

https://github.com/vllm-project/vllm/
github_pr

[Frontend][Rust] Bound chat-template evaluation to prevent DoS (#52025)

Upstream fix in progress (PR #52163 · vllm-project/vllm, state=open)

https://github.com/vllm-project/vllm/pull/52163
generic

[Bug]: Rust frontend renders caller-supplied chat templates with no evaluation budget: a 116-byte request body costs 55 CPU-seconds · Issue #52025 · vllm-project/vllm · GitHub

https://github.com/vllm-project/vllm/issues/52025

Vendor Advisories for CVE-2026-90878(1)

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

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 22× in last 7d / 22× 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. 2026-09-19 12:29 UTCEG score recompute
  2. 2026-09-19 12:29 UTCGHSA enrichment
  3. 2026-09-18 19:28 UTCEPSS rescore
  4. 2026-09-18 13:06 UTCEG score recompute
  5. 2026-09-18 13:06 UTCGHSA enrichment
  6. 2026-09-17 19:32 UTCEPSS rescore
  7. 2026-09-17 13:42 UTCGHSA enrichment
  8. 2026-09-16 14:16 UTCEG score recompute
  9. 2026-09-16 14:16 UTCGHSA enrichment
  10. 2026-09-16 14:09 UTCEPSS rescore
  11. 2026-09-16 05:15 UTCEPSS rescore
  12. 2026-09-15 14:52 UTCGHSA enrichment
  13. 2026-09-15 14:33 UTCEG score recompute
  14. 2026-09-15 14:33 UTCGHSA enrichment
  15. 2026-09-15 14:31 UTCNVD updateCVSS v4 → 2.1
  16. 2026-09-15 14:03 UTCEG score recompute
  17. 2026-09-15 14:03 UTCGHSA enrichment
  18. 2026-09-15 14:02 UTCMITRE cvelistV5CVSS v4 → 5.3
  19. 2026-09-15 05:34 UTCEG score recompute
  20. 2026-09-15 05:32 UTCNVD updateCVSS v4 → 2.1
  21. 2026-09-15 04:29 UTCEG score recompute
  22. 2026-09-15 04:28 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-90878?
CVE-2026-90878 is a medium vulnerability published on September 15, 2026. A vulnerability was determined in vllm-project vLLM up to 0.27.1. This affects an unknown part of the file /v1/chat/completions of the component Jinja Template Rendering. This manipulation of the argument chat_template causes resource consumption. The attack can be initiated remotely. The exploit…
When was CVE-2026-90878 disclosed?
CVE-2026-90878 was first published in the National Vulnerability Database on September 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-90878 actively exploited?
CVE-2026-90878 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 76.8% of all scored CVEs.
What is the CVSS score of CVE-2026-90878?
CVE-2026-90878 has a CVSS v3 base score of 4.3 (NVD).
How do I remediate CVE-2026-90878?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-90878, 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

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