GHSA-8qqm-fp2q-v734: github.com/zalando/skipper (CVE-2026-65838)

Package	Ecosystem	Affected	Fixed in
github.com/zalando/skipper	Go	<0.27.26	0.27.26

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Skipper (github.com/zalando/skipper) versions before 0.27.26 are affected. When a request declares a Content-Length larger than the configured maximum body size, Open Policy Agent receives an empty parsed body while the full payload still reaches the upstream, so deny-on-presence Rego policies fail open. An attacker who can send such requests can bypass body-based authorization. Upgrade to 0.27.26 or later; the advisory's mitigation section suggests writing policies that also check for an oversized body, such as the truncated_body input attribute.

Written 1 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
8.2	High	3.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0046, the 40th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:13 UTC First seen by agentprime
31 Oct 2026, 14:13 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.