Summary
Using CookieJar.load() with untrusted input may allow arbitrary code execution.
Workaround
If an application does allow attacker controlled files to be loaded, a workaround on older releases would be to sanitise the files before loading.
Patch: https://github.com/aio-libs/aiohttp/commit/dcf40f30637e8752c76781cf6703b5a236749a00
Impact
Most applications using this function will be doing so with the user's own data, so this is unlikely to affect many applications.
Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect. Typical impact: arbitrary code execution or logic abuse.
CVE-2026-34993 has a CVSS score of 6.4 (Medium). The vector is requires local access, high privileges required, and user interaction required. 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 (3.14.0); 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.
Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-34993? CVE-2026-34993 is a medium-severity insecure deserialization vulnerability in aiohttp (pip), affecting versions < 3.14.0. It is fixed in 3.14.0. Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect.
- How severe is CVE-2026-34993? CVE-2026-34993 has a CVSS score of 6.4 (Medium). 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 aiohttp are affected by CVE-2026-34993? aiohttp (pip) versions < 3.14.0 is affected.
- Is there a fix for CVE-2026-34993? Yes. CVE-2026-34993 is fixed in 3.14.0. Upgrade to this version or later.
- Is CVE-2026-34993 exploitable, and should I be worried? Whether CVE-2026-34993 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-2026-34993 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-2026-34993? Upgrade
aiohttpto 3.14.0 or later.