CVE-2026-86043
Skipper: OPA body-authz bypass: truncated_body mitigation fails open on chunked/HTTP-2 (incomplete fix CVE-2026-50197)
Description
Skipper is an HTTP router and reverse proxy for service composition. Prior to version 0.27.37, the opaAuthorizeRequestWithBody filter can authorize an oversized request after Skipper truncates the body presented to Open Policy Agent because the input.truncated_body signal is derived from Content-Length rather than the actual read result. In filters/openpolicyagent/openpolicyagent.go, ExtractHttpBodyOptionally truncates bodies at maxBodyBytes, while filters/openpolicyagent/internal/envoy/skipperadapter.go copies the request headers without adding a Content-Length value that reflects the truncation. For an HTTP/1.1 request using Transfer-Encoding: chunked or an HTTP/2 request without Content-Length, a body-inspecting policy that follows the prior mitigation and permits input.truncated_body equal to false can evaluate only the truncated prefix, allow the request, and then forward the full oversized body to the protected upstream. This residual issue is distinct from CVE-2026-50197. This issue is fixed in version 0.27.37.
INFO
Published Date :
Sept. 16, 2026, 7:17 p.m.
Last Modified :
Sept. 16, 2026, 8:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update Skipper to version 0.27.37 or later.
- Ensure Content-Length reflects body truncation.
- Review OPA policies for body size checks.
- Validate authorization with oversized requests.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-86043.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-86043 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-86043
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2026-86043 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-86043 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Sep. 16, 2026
Action Type Old Value New Value Added Reference https://github.com/zalando/skipper/security/advisories/GHSA-5gpm-rgj3-9q76 Added SSVC {'id': 'CVE-2026-86043', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-09-16T19:38:03.907390Z'} -
New CVE Received by [email protected]
Sep. 16, 2026
Action Type Old Value New Value Added Description Skipper is an HTTP router and reverse proxy for service composition. Prior to version 0.27.37, the opaAuthorizeRequestWithBody filter can authorize an oversized request after Skipper truncates the body presented to Open Policy Agent because the input.truncated_body signal is derived from Content-Length rather than the actual read result. In filters/openpolicyagent/openpolicyagent.go, ExtractHttpBodyOptionally truncates bodies at maxBodyBytes, while filters/openpolicyagent/internal/envoy/skipperadapter.go copies the request headers without adding a Content-Length value that reflects the truncation. For an HTTP/1.1 request using Transfer-Encoding: chunked or an HTTP/2 request without Content-Length, a body-inspecting policy that follows the prior mitigation and permits input.truncated_body equal to false can evaluate only the truncated prefix, allow the request, and then forward the full oversized body to the protected upstream. This residual issue is distinct from CVE-2026-50197. This issue is fixed in version 0.27.37. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Added CWE CWE-863 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/86xxx/CVE-2026-86043.json">CVE-2026-86043</a> Added Reference https://github.com/zalando/skipper/commit/2cfceabaa6ff0af65b312dcb9bcbe84691b9d507 Added Reference https://github.com/zalando/skipper/releases/tag/v0.27.35 Added Reference https://github.com/zalando/skipper/security/advisories/GHSA-5gpm-rgj3-9q76 Added Reference https://github.com/zalando/skipper/tree/v0.27.35