Summary
Plug: Unbounded buffer accumulation in multipart header parsing causes denial of service
An Allocation of Resources Without Limits or Throttling vulnerability in Plug.Conn.read_part_headers/2 allows an unauthenticated attacker to exhaust server memory by sending a crafted multipart/form-data request, causing a denial of service.
Details
Plug.Conn.read_part_headers/2 in lib/plug/conn.ex does not obey its :length parameter. There is no upper bound on the size of the accumulated buffer. By contrast, the sibling function read_part_body has an explicit byte_size(acc) > length guard that stops accumulation once a limit is reached. No such guard exists in read_part_headers.
References
Impact
This is a denial-of-service vulnerability. Any application using Plug.Parsers with the :multipart parser, or calling Plug.Conn.read_part_headers/2 directly, is affected. An unauthenticated remote attacker can trigger the issue by sending crafted HTTP requests with no special privileges.
The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap. Typical impact: resource exhaustion leading to denial of service.
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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plug to 1.15.4 or later; plug to 1.16.3 or later; plug to 1.17.1 or later; plug to 1.18.2 or later; plug to 1.19.2 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-8468? CVE-2026-8468 is a high-severity allocation of resources without limits or throttling vulnerability in plug (erlang), affecting versions >= 1.4.0, < 1.15.4. It is fixed in 1.15.4, 1.16.3, 1.17.1, 1.18.2, 1.19.2. The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap.
- Which versions of plug are affected by CVE-2026-8468? plug (erlang) versions >= 1.4.0, < 1.15.4 is affected.
- Is there a fix for CVE-2026-8468? Yes. CVE-2026-8468 is fixed in 1.15.4, 1.16.3, 1.17.1, 1.18.2, 1.19.2. Upgrade to this version or later.
- Is CVE-2026-8468 exploitable, and should I be worried? Whether CVE-2026-8468 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-2026-8468 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-2026-8468?
- Upgrade
plugto 1.15.4 or later - Upgrade
plugto 1.16.3 or later - Upgrade
plugto 1.17.1 or later - Upgrade
plugto 1.18.2 or later - Upgrade
plugto 1.19.2 or later
- Upgrade