Critical CSRF

CVE-2026-49871 — Apache APISIX cas-auth Plugin CSRF Vulnerability (CVE-2026-49871)

Cross-Site Request Forgery (CSRF) vulnerability in the cas-auth plugin under default configurations. This defect allows a remote attacker that manages to send a victim to a webpage controlled by them can cause the victim's browser to become authenticated as a different identity. Actions the victim takes upstream are then attributed to attackers identity. This issue affects Apache APISIX: from 3.0.0 through 3.16.0. Users are recommended to upgrade to version 3.17.0, which fixes the issue.

Published Jun 19, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: apache

Low

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 0.4% (30-day exploitation probability)+4
Technical severity (critical)+10

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

0.35%

ahead of 27% of scored CVEs · Oct 14, 2026

Affects

Apache Software Foundation

Apisix

CVSS base

9.3

Critical · 3 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

None

none · proof-of-concept · active

Automatable

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.

Identify exposed assets running the affected vendor/product/version combinations (Apache Software Foundation Apisix).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Exploitation requires user interaction: tighten email/web filtering and warn affected users.
Search available logs for exploit probes matching the vulnerability class (csrf), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Apache Software Foundation	Apisix	≥ 3.0.0 and < 3.17.0	Vulnerable	NIST National Vulnerability Database
Apache Software Foundation	Apisix	≥ 3.0.0 and ≤ 3.16.0	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

Required

Scope

Changed

Confidentiality

High

Integrity

High

Availability

None

Every base score collected

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

Score	Version	Severity	Expl.	Impact	Scored by
2.1	CVSS 4.0	Low	—	—	security@apache.org via NIST National Vulnerability Database
2.1	CVSS 4.0	Low	—	—	apache via CVE Program (cve.org) e CISA ADP
9.3	CVSS 3.1	Critical	2.8	5.8	nvd@nist.gov via NIST National Vulnerability Database

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-352 · Cross-Site Request Forgery (CSRF)

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.35%

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).

web/proxy/WAF logsnetwork IDS/IPS

Analysis and videos

CVE-2026-49871: Apache APISIX cas-auth Plugin CSRF Vulnerability
A Cross-Site Request Forgery flaw in the cas-auth plugin of Apache APISIX under default configurations may let a remote attacker lead a victim's browser into an authenticated state tied to a different identity. The record reports a CVSS 3.1 base score of 9.3 from NVD and a fix in version 3.17.0. The sources consulted show no KEV listing and no confirmed exploitation.

Timeline

What happened to this CVE, newest first.

2026
Affected products added · apache software foundation/apache apisix
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
CVSS changed · 9.3
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Jun 19, 2026 · apache

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

2 on the record

lists.apache.org/thread/1ozsnss0lof4gpwq763d66oxwxt3sycp
Vendor Advisory, Mailing List, vendor-advisory, NIST National Vulnerability Database
www.openwall.com/lists/oss-security/2026/06/19/14
Third Party Advisory, NIST National Vulnerability Database

Elsewhere on this site

Apache Software Foundation
every CVE for this vendor

CSRF
same class

CWE-352
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-75020 LDAP Injection in Apache Software Foundation Apisix Aug 27, 2026
High CVE-2026-74848 HTTP Request Smuggling in Apache Software Foundation Apisix Aug 27, 2026
High CVE-2026-75005 Inefficient Algorithmic Complexity vulnerability in Apache APISIX. A single small… Aug 27, 2026
High CVE-2026-63041 Reliance on Untrusted Inputs in a Security Decision vulnerability in Apache APISIX. This… Aug 26, 2026
Critical CVE-2026-49230 Apache APISIX jwe-decrypt Authentication Bypass via Integrity Check Validation Jun 19, 2026
High CVE-2026-48895 Apache APISIX: Cas-auth Host header influence on CAS service URL Jun 19, 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-2026-49871 is "Apache APISIX cas-auth Plugin CSRF Vulnerability (CVE-2026-49871)", rated Critical. It affects Apisix (Apache Software Foundation); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 9.3 describes technical severity. EPSS 0.35% 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.