CVE Intelligence
High Access control

CVE-2026-86043 — Skipper: OPA body-authz bypass: truncated_body mitigation fails open on chunked/HTTP-2 (incomplete fix CVE-2026-50197)

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.

Published Sep 16, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: GitHub_M

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.5% (30-day exploitation probability)+6
  • Technical severity (high)+6
  • CISA SSVC: exploitation "poc"+5
  • Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.45%
ahead of 38% of scored CVEs · Oct 15, 2026
Affects
Zalando
Skipper
CVSS base
7.5
High · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
Proof of concept
none · proof-of-concept · active
Automatable
Yes
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Zalando Skipper).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Search available logs for exploit probes matching the vulnerability class (access control), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Zalando Skipper version < 0.27.37 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
7.5 CVSS 3.1 High 3.9 3.6 security-advisories@github.com via NIST National Vulnerability Database
7.5 CVSS 3.1 High — — GitHub_M via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N (score shown at the top: security-advisories@github.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-863 · Incorrect Authorization

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Audit administrative actions and access to resources outside each user’s normal pattern.
web/proxy/WAF logsnetwork IDS/IPSauthentication logsapplication logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · zalando/skipper
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 15, 2026
  • CVSS changed · 7.5
    Oct 15, 2026 · NIST National Vulnerability Database
  • Source status changed · → Deferred
    Oct 15, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 15, 2026 · NIST National Vulnerability Database
  • CVE published
    Sep 16, 2026 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

4 on the record

Elsewhere on this site

Zalando
every CVE for this vendor
Access control
same class
CWE-863
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-65838 Skipper: an oversized declared-`Content-Length` body still hands OPA an empty `parsed_body`, so deny-on-presence Rego policies fail OPEN while the full payload reaches upstream Sep 14, 2026
  • CVE-2026-54246 Skipper routesrv-no-auth: All routesrv API Endpoints Lack Authentication Sep 14, 2026
  • CVE-2026-54247 Skipper: Unbounded Request Body Read in Admission Webhook Causes Memory Exhaustion DoS Sep 14, 2026
  • CVE-2026-65604 Skipper Incomplete Fix for CVE-2026-50197 Policy Bypass Jul 23, 2026
  • CVE-2026-50197 Skipper: opaAuthorizeRequestWithBody filter bypasses OPA policy on Transfer-Encoding: chunked / HTTP/2 requests Jul 17, 2026
  • CVE-2026-24470 Skipper Ingress Controller Allows Unauthorized Access to Internal Services via ExternalName Jan 26, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-86043 is "Skipper: OPA body-authz bypass: truncated_body mitigation fails open on chunked/HTTP-2 (incomplete fix CVE-2026-50197)", rated High. It affects Skipper (Zalando); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 0.45% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

Comments

Moderated technical discussion. Read the community guidelines.

No comments yet.

Sign in or create an account to comment and suggest corrections.