Summary
pyasn1 has quadratic-time denial of service in constructed string and indefinite-length ANY decoding
Impact
If an application passes attacker-controlled ASN.1 to the affected decode() or StreamingDecoder path without an adequate input or resource limit, a megabyte-scale value can occupy a decoding worker for seconds. Repeated inputs can exhaust available CPU. Whether this is reachable before authentication, or through a particular protocol, depends on the application; the library finding alone does not establish those conditions. No confidentiality or integrity impact is claimed.
CVE-2026-119195 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.6.5); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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pyasn1 0.6.5 replaces the growing bytes accumulator with a list of fragments and joins them once after decoding in all three affected loops. The OCTET STRING base-class change also covers the inheriting character-string decoders. This removes the repeated copying while preserving the assembled decoded value.
Frequently Asked Questions
- What is CVE-2026-119195? CVE-2026-119195 is a high-severity security vulnerability in pyasn1 (pip), affecting versions <= 0.6.4. It is fixed in 0.6.5.
- How severe is CVE-2026-119195? CVE-2026-119195 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of pyasn1 are affected by CVE-2026-119195? pyasn1 (pip) versions <= 0.6.4 is affected.
- Is there a fix for CVE-2026-119195? Yes. CVE-2026-119195 is fixed in 0.6.5. Upgrade to this version or later.
- Is CVE-2026-119195 exploitable, and should I be worried? Whether CVE-2026-119195 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-119195 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-119195? Upgrade
pyasn1to 0.6.5 or later.