CVE-2026-16728

Description

undici's retry interceptor can deliver a response whose body length does not match the Content-Length header exposed to the application after a retry or resume of a partial response. In undici before 6.28.0, from 7.0.0 up to before 7.29.0, and from 8.0.0 up to before 8.9.0, a malicious or faulty upstream can return a partial response with a mismatched framing header, close the socket early, and have the retry interceptor assemble a body of a different length while the original Content-Length stays attached. Applications that use the retry interceptor and forward upstream headers and bodies downstream, such as proxies or gateways, may then emit an invalid HTTP response with a stale Content-Length, leading to downstream response desynchronization, connection hangs, or response corruption. Exploitation requires the retry interceptor enabled, an upstream returning a mismatched partial response, and a downstream forwarder that does not remove or recalculate Content-Length. The issue is fixed in undici 6.28.0, 7.29.0, and 8.9.0.

CVSS Metrics

• v3.1•MEDIUM•Score: 4.8CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
• v3.1•MEDIUM•Score: 6.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

EPSS Trends

Current EPSS score: 0.18%• Percentile: 7%

Techniques & Countermeasures

• CWE-444•Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

  The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.

Affected Systems

• chainguard•actions-runner

  < 2.336.0-r5

• chainguard•code-server

  < 4.130.0-r5

• chainguard•commercial-gitlab-rails-ee-19.1

  all

• chainguard•commercial-gitlab-rails-ee-19.2

  all

• chainguard•commercial-gitlab-rails-ee-19.3

  all

• chainguard•commercial-gitlab-rails-ee-fips-19.1

  all

• chainguard•kibana-8.19

  < 8.19.20-r2

• chainguard•kibana-8.19-bitnami

  < 8.19.20-r2

• chainguard•kibana-8.19-iamguarded

  < 8.19.20-r2

• chainguard•kibana-9.1

  all

• chainguard•kibana-9.1-iamguarded

  all

• chainguard•kibana-9.2

  < 9.2.8-r19

• chainguard•kibana-9.2-iamguarded

  < 9.2.8-r19

• chainguard•kibana-9.3

  all

• chainguard•kibana-9.3-iamguarded

  all

• chainguard•langfuse-3

  < 3.225.0-r3

• chainguard•langfuse-3-compat

  < 3.225.7-r6

• chainguard•langfuse-3-worker

  < 3.225.0-r3

• chainguard•langfuse-4

  < 4.3.1-r3

• chainguard•langfuse-4-worker

  < 4.3.1-r3

• chainguard•langfuse-fips-3

  < 3.224.3-r9

• chainguard•langfuse-fips-3-worker

  < 3.224.3-r9

• chainguard•langfuse-fips-4

  < 4.4.0-r0

• chainguard•langfuse-fips-4-worker

  < 4.4.0-r0

• chainguard•npm-12

  < 12.0.2-r2

• chainguard•pelias-api

  < 7.8.0-r7

• chainguard•prism

  < 5.16.0-r2

• chainguard•pulumi-language-nodejs

  < 3.256.0-r1

• chainguard•renovate

  < 44.23.3-r1 | < 44.11.4-r0 | < 44.11.3-r0

• chainguard•saf

  < 1.7.0-r0

• chainguard•vitess-24

  < 24.0.2-r10

• chainguard•vitess-24-compat

  < 24.0.3-r7

• wolfi•code-server

  < 4.130.0-r5

• wolfi•langfuse-3

  < 3.225.0-r3

• wolfi•langfuse-3-compat

  < 3.225.7-r6

• wolfi•langfuse-3-worker

  < 3.225.0-r3

• wolfi•npm-12

  < 12.0.2-r2

• wolfi•prism

  < 5.16.0-r2

• wolfi•pulumi-language-nodejs

  < 3.256.0-r1

• wolfi•renovate

  < 44.23.3-r1 | < 44.11.4-r0 | < 44.11.3-r0

• wolfi•saf

  < 1.7.0-r0

• wolfi•vitess-24

  < 24.0.2-r10

• wolfi•vitess-24-compat

  < 24.0.3-r7

• debian•node-undici

  all | all | < 8.9.0+dfsg+~cs3.2.0-1

• ubuntu•node-undici

  all | all

• nodejs•undici

  < 6.28.0 | ≥ 7.0.0, < 7.29.0 | ≥ 8.0.0, < 8.9.0

• Npm•undici

  < 6.28.0 | ≥ 7.0.0, < 7.29.0 | ≥ 8.0.0, < 8.9.0

• undici•undici

  < 6.28.0 | ≥ 7.0.0, < 7.29.0 | ≥ 8.0.0, < 8.9.0

References (18)

• https://github.com/nodejs/undici/security/advisories/GHSA-8xcm-r25x-g524
• https://cna.openjsf.org/security-advisories.html
• https://ubuntu.com/security/CVE-2026-16728
• https://www.cve.org/CVERecord?id=CVE-2026-16728
• https://security-tracker.debian.org/tracker/CVE-2026-16728
• https://nvd.nist.gov/vuln/detail/CVE-2026-16728
• https://github.com/nodejs/undici/commit/1b5a5312c3a7d7a30c31bf0d000b39a8a2531e1c
• https://github.com/nodejs/undici/commit/2b3f749336d356bbbc50192f87f6cf7bc714721a
• https://github.com/nodejs/undici/commit/4a9dafb16ff43880cf590e6d9c2aeee25fbff6d7
• https://github.com/nodejs/undici/commit/4fd5a0c61e627f928b7003adc4ffe1e55ec63420
• https://github.com/nodejs/undici/commit/cba3a52ac2e7abcc4e656d82af8579ea82c2bb9e
• https://github.com/nodejs/undici/commit/e11a68ed4ff345c79402476f7a00d473443e318d
• https://hackerone.com/reports/3828685
• https://github.com/nodejs/undici
• https://github.com/nodejs/undici/releases/tag/v6.28.0
• https://github.com/nodejs/undici/releases/tag/v7.29.0
• https://github.com/nodejs/undici/releases/tag/v8.9.0
• https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/16xxx/CVE-2026-16728.json