{"answers":{"affected":"3 open source packages ship an affected version, including vllm. It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-73556 exists.","fix":"Upgrade vllm to 0.26.0 or later.","what":"CVE-2026-73556 is a medium-severity denial of service vulnerability in Vllm Vllm, published on 13 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-73556 and fix it if it is affected.\n\nWhat it is: CVE-2026-73556 is a medium-severity denial of service vulnerability in Vllm Vllm, published on 13 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-73556 exists.\n\nAffected packages and fixed versions:\n- vllm (PyPI): affected all versions; fixed in 0.26.0\n- vllm (PyPI): affected all versions; fixed in 0.26.0\n- vllm (PyPI): affected all versions; fixed in 0.26.0\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-73556/ (Markdown: https://insights.sbomify.com/CVE-2026-73556/index.md)","id":"CVE-2026-73556","markdown":"https://insights.sbomify.com/CVE-2026-73556/index.md","name":"CVE-2026-73556","record":{"aliases":["GHSA-48jh-3gj7-fg8v","MINI-72r3-55xc-c6pj","MINI-fxw5-mhjq-jm6p","MINI-hhc6-w7j8-737j","PYSEC-2026-3933"],"analysis":{"component_type":"server_software","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"LLM inference engine","requires_auth":"none","summary":"An unauthenticated attacker can cause denial of service in vLLM by submitting a catastrophic regular expression to the structured outputs endpoint.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"vllm","vendor":"vllm"}],"cvss":{"score":5.3,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","version":"3.1"},"cwes":[{"id":"CWE-400","name":"Uncontrolled Resource Consumption"},{"id":"CWE-1333","name":"Inefficient Regular Expression Complexity"}],"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.","ecosystems":["PyPI"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"vLLM: ReDoS via structured_outputs.regex in the lm-format-enforcer backend (no compile timeout) — missed sibling of GHSA-rwxx-mrjm-wc2m","id":"CVE-2026-73556","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"PyPI","product":"vllm:vllm","products":["vllm:vllm"],"type":"denial_of_service","year":"2026"},"n_packages":3,"n_references":4,"next":{"headline":"vLLM: Incomplete CVE-2025-62164 remediation can be bypassed by concurrent prompt parts","id":"CVE-2026-73557"},"packages":[{"ecosystem":"PyPI","fixed":["0.26.0"],"introduced":["0"],"last_affected":[],"package":"vllm","purl":null,"source":"GHSA-48jh-3gj7-fg8v"},{"ecosystem":"PyPI","fixed":["0.26.0"],"introduced":["0"],"last_affected":[],"package":"vllm","purl":"pkg:pypi/vllm","source":"GHSA-48jh-3gj7-fg8v"},{"ecosystem":"PyPI","fixed":["0.26.0"],"introduced":["0"],"last_affected":[],"package":"vllm","purl":"pkg:pypi/vllm","source":"PYSEC-2026-3933"}],"prev":{"headline":"vLLM: Unauthenticated Internal Path and Username Disclosure via Validation Error Messages","id":"CVE-2026-73555"},"products":["vllm"],"published":"2026-08-13","related":[{"cvss_score":10,"headline":"vLLM Vulnerable to Remote Code Execution via Mooncake Integration","id":"CVE-2025-32444","kev_date_added":null,"published":"2025-04-30"},{"cvss_score":9.8,"headline":"vLLM leaks a heap address when PIL throws an error","id":"CVE-2026-22778","kev_date_added":null,"published":"2026-02-02"},{"cvss_score":9.8,"headline":"vLLM Allows Remote Code Execution via PyNcclPipe Communication Service","id":"CVE-2025-47277","kev_date_added":null,"published":"2025-05-20"},{"cvss_score":9.8,"headline":"Remote Code Execution in vllm-project/vllm","id":"CVE-2024-11041","kev_date_added":null,"published":"2025-03-20"},{"cvss_score":9.1,"headline":"vLLM: OpenAI auth bypass","id":"CVE-2026-48746","kev_date_added":null,"published":"2026-06-22"},{"cvss_score":9.1,"headline":"vLLM Allows Remote Code Execution via Mooncake Integration","id":"CVE-2025-29783","kev_date_added":null,"published":"2025-03-19"},{"cvss_score":8.8,"headline":"vLLM 0.9.2 before 0.24.0 SSRF via X-Request-Id in P2pNcclConnector","id":"CVE-2026-116176","kev_date_added":null,"published":"2026-10-25"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CC BY 4.0","name":"PyPA Advisory Database","prefix":"PYSEC"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"yes","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-08-14","vendors":["vllm-project"]},"summary":"An unauthenticated attacker can cause denial of service in vLLM by submitting a catastrophic regular expression to the structured outputs endpoint.","url":"https://insights.sbomify.com/CVE-2026-73556/"}