CVE-2026-8468
Fix: elixir-plug/plug@2cb7958CVE-2026-8468 is a CWE-770 vulnerability in plug. O3 Security confirms whether CVE-2026-8468 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Unbounded buffer accumulation in multipart header parsing causes denial of service in plug
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-8468.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
plug💧plug💧plug💧plug💧plugReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Hex packages — download data is not available via public APIs for these ecosystems.
Description
Allocation of Resources Without Limits or Throttling vulnerability in plug_project plug allows denial of service via unbounded buffer accumulation in multipart header parsing.
'Elixir.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. An unauthenticated remote attacker can exhaust server memory by sending a crafted multipart/form-data request, causing a denial of service.
This issue affects plug from 1.4.0 before 1.15.4, 1.16.3, 1.17.1, 1.18.2, and 1.19.2.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💧Hex | plug | ≥ 1.4.0&&< 1.15.4 | 1.15.4 |
| 💧Hex | plug | ≥ 1.16.0&&< 1.16.3 | 1.16.3 |
| 💧Hex | plug | ≥ 1.17.0&&< 1.17.1 | 1.17.1 |
| 💧Hex | plug | ≥ 1.18.0&&< 1.18.2 | 1.18.2 |
| 💧Hex | plug | ≥ 1.19.0&&< 1.19.2 | 1.19.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for plug. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update plug to 1.15.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-8468 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-8468 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-8468. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-8468 in your dependencies?
O3 detects CVE-2026-8468 across Hex dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.