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Fencer Intel
medium 5.3

CVE-2026-81829 json

Smallrye-jwt: quarkus-smallrye-jwt: smallrye-jwt: unauthenticated same-origin ssrf via unsanitized jwt kid header in awsalbkeyresolver

published last mo. modified last mo. also EUVD-2026-81617

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 48%
public exploits
0
none known

Summary

A flaw was found in SmallRye JWT's AwsAlbKeyResolver, which is used by applications to verify JSON Web Tokens signed by AWS Application Load Balancers. When the AWS_ALB key provider is configured, the resolver constructs the key-fetch URL by directly concatenating the attacker-controlled kid header value from an inbound JWT without sanitizing path traversal characters or query-string separators. This allows an unauthenticated remote attacker to force the application server to issue GET requests to arbitrary paths on the same origin as the configured key endpoint. As a result, non-public endpoints or internal data reachable on that origin may be read by the attacker before JWT signature verification takes place.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-81829 updated cvss 5.3

smallrye-jwt: quarkus-smallrye-jwt: smallrye-jwt: Unauthenticated same-origin SSRF via unsanitized JWT kid header in AwsAlbKeyResolver

  • Red Hat Exploit Intelligence exploit-intelligence/agent-client-rhel9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat build of Apicurio Registry 3 quarkus-smallrye-jwt, smallrye-jwt 4.6.2.redhat-00001
    affected: workaround, no fix available, no fix planned “Out of support scope”
  • Red Hat build of Quarkus smallrye-jwt 4.6.2.redhat-00001 Red Hat JBoss Enterprise Application Platform 8 smallrye-jwt 4.6.2.redhat-00001 Red Hat JBoss Enterprise Application Platform Expansion Pack smallrye-jwt 4.6.2.redhat-00001
    affected: workaround, no fix available “Fix deferred”
  • Red Hat build of Quarkus 3.27.5.SP2
    fixed: vendor fix RHSA-2026:69470
  • Red Hat build of Quarkus 3.33.3.SP2
    fixed: vendor fix RHSA-2026:69440

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.59% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected products

  • Red Hat Red Hat build of Quarkus 3.27.5.SP2
  • Red Hat Red Hat build of Quarkus 3.33.3.SP2
  • Red Hat Exploit Intelligence
  • Red Hat Red Hat build of Apicurio Registry 3
  • Red Hat Red Hat build of Quarkus
  • Red Hat Red Hat JBoss Enterprise Application Platform 8
  • Red Hat Red Hat JBoss Enterprise Application Platform Expansion Pack

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.