CVE-2026-73556: vllm-project vllm Uncontrolled Resource Consumption
Vulnerability summary
CVE-2026-73556 is a medium (CVSS 5.3) Uncontrolled Resource Consumption vulnerability in vllm-project vllm. EPSS estimates a 0.52% chance of exploitation in the next 30 days, higher than 42.9% of scored vulnerabilities.
Timeline
- 13-08-2026PublishedVulnerability first disclosed.
- 14-08-2026Last modifiedVulnerability information updated.
Description
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 metrics
4 scores · 4 sources · 1 version- OSV · PypiEcosystem advisory · calculated5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- OSV · ChainguardEcosystem advisory · calculated5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- NVDNIST5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
EPSS trend
Probability
0.52%
Chance of exploitation in the next 30 days
Percentile
43%
Versus all other CVEs
30-day change
+0.20 pp
From 0.32% on 21-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-400Uncontrolled Resource ConsumptionThe product does not properly control the allocation and maintenance of a limited resource.
- CWE-1333Inefficient Regular Expression ComplexityThe product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.
Affected systems
Chainguard5 products
- kserve-huggingfaceserver-cuda-13.3All versions (No fix recorded)
- lmcache-cuda-12.8All versions (No fix recorded)
- nemo-rl-cuda-13.0-vllmAll versions (No fix recorded)
- py3.10-vllm-cuda-12.4All versions (No fix recorded)
- py3.12-vllm-cuda-12.4All versions (No fix recorded)
PyPI1 product
- vllm< 0.26.0
Vllm1 product
- vllm< 0.26.0
Vllm-project1 product
- vllm< 0.26.0
4 vendors · 8 products
References
9 links- github.com/vllm-project/vllm/security/advisories/GHSA-48jh-3gj7-fg8vX Refsource CONFIRMWEBAdvisoryVendor Advisory
- github.com/vllm-project/vllm/commit/c9a788eedc412acceaa5112e0d44624b49841577X Refsource MISCWEBFIXPatch
- github.com/vllm-project/vllmPACKAGE
- pypi.org/project/vllmPACKAGE