CVE-2026-31835
Vaultwarden is a Bitwarden-compatible server written in Rust. In versions 1.35.4 and earlier, the WebAuthn authentication flow in `validate_
CVSS
5.4
Medium
EPSS
0.2%
p4
KEV
—
Exploit Today
1
0-100
Published: May 5, 2026 · Last modified: Jul 25, 2026 · CWE-345
0.2%EPSS · 30 days0.2%
2026-10-022026-10-29
Vaultwarden is a Bitwarden-compatible server written in Rust. In versions 1.35.4 and earlier, the WebAuthn authentication flow in `validate_webauthn_login()` updates persistent credential metadata (1backup_eligible1 and 1backup_state flags1) based on unverified `authenticatorData` before signature validation is performed. An attacker who knows a user's password but cannot produce a valid WebAuthn signature can permanently modify the stored backup flags for that user's credential. If signature verification fails, the database update is not rolled back. This can result in a persistent denial of service of WebAuthn two-factor authentication for affected credentials. This issue has been fixed in version 1.35.5.
CVECVSSEPSSKEVRExploitTitleMod.
CVE-2026-631155.3 MED—
———ActivityPub is a multi-tenant ActivityPub server for Ghost, built with Fedify. From 1.0.0 until 1.2.6, the `Undo` handler allows a remote federated server to cause the service to act on a `follow` or `repost` as though the activity came from a different account. This permits removal of an existing `follow` relationship or `repost` belonging to another account without that account's involvement. No private data is exposed and content is not modified; the affected relationships can be re-established. Services proxying to Ghost's hosted ActivityPub server have already been updated, while self-hosted services require an updated image and redeployment. This issue is fixed in version 1.2.6.10hCVE-2026-1192897.1 HIG—
———Zuke is a code-first, strongly typed build automation system for Deno. Prior to 1.10.0, the @zuke/gh githubWorkflow(...) gate correlates a dispatched workflow run using only a display-title marker that is visible in the workflow run list and can be copied by another dispatcher. In configurations where the external workflow repository grants workflow_dispatch permission to a party not equally trusted by the releasing repository, an attacker can dispatch a run with the marker and cause the gate to adopt its conclusion without verifying the event, ref, or creation window. A passing substituted run can authorize an unvalidated release, while a failed or cancelled run can block a valid release, and the persisted adopted run ID preserves the substitution across build resume. This issue is fixed in version 1.10.0.15hCVE-2026-1194225.9 MED—
———Juspay Hyperswitch before 1.128.0 contains an authentication bypass vulnerability that allows unauthenticated attackers to forge payment status updates because the Worldpayxml connector's verify_webhook_source always returns true without enforced mTLS. Attackers knowing the merchant_id and Worldpay orderCode can POST unsigned XML with lastEvent SETTLED to the worldpayxml webhook endpoint, marking unpaid payments as charged or triggering refund, dispute and payout events.13hCVE-2026-930086.8 MED—
——0A flaw was found in dnsmasq. When following a CNAME in a DNS response, the resolver can cache records for the CNAME target without checking that those records belong to the responding server's authorized zone. In split-DNS deployments that send some domains to a specific upstream, an attacker who controls that upstream can inject cache entries for unrelated names. Later clients may then receive attacker-chosen addresses for those names.1dCVE-2026-110985—2.3%
——1A Kafka broker using SASL/OAUTHBEARER with the default validator (sasl.oauthbearer.jwt.validator.class=DefaultJwtValidator) selects its implementation from configuration. When sasl.oauthbearer.jwks.endpoint.url is set, the validator verifies the JWT signature. When that URL is unset (the default) and no verification key resolver is supplied, DefaultJwtValidator silently falls back to ClientJwtValidator, which does not verify the JWT signature, algorithm, or issuer - and the broker starts with no warning or error. This is the residual of CVE-2026-33557, whose fix restored signature verification only on the path where the JWKS endpoint URL is set.
Impact:
A broker in this state accepts any structurally valid JWT, including "alg":"none" tokens. An unauthenticated remote attacker who can reach the listener can forge a token asserting any principal - including configured superusers - and gain full access to the cluster. Only brokers that enable SASL/OAUTHBEARER validation without a JWKS endpoint URL (and without a custom verification key resolver) are affected; brokers that set the URL verify signatures and are not affected. Unlike CVE-2026-110952 (issuer/audience not enforced by default), here no signature is verified at all.
Mitigation (all affected versions, no upgrade required):
Set sasl.oauthbearer.jwks.endpoint.url for every listener/mechanism that uses OAuthBearerValidatorCallbackHandler, or configure a signature-verifying sasl.oauthbearer.jwt.validator.class.
Resolution:
From Apache Kafka 4.2.2, 4.3.1, and 4.4.0: a broker that would fall back to the non-verifying ClientJwtValidator fails to start with a ConfigException instead of running without signature verification (secure by default).2dCVE-2026-110952—2.1%
——1A Kafka broker that authenticates clients with SASL/OAUTHBEARER using the bundled JWKS-backed validator always verifies the JWT signature, but two further checks are only performed when explicitly configured:
- The issuer (iss) claim is verified only when sasl.oauthbearer.expected.issuer is set. When it is unset, a validly-signed token carrying the expected audience is accepted regardless of which issuer minted it.
- An audience (aud) claim is required only when sasl.oauthbearer.expected.audience is set. When it is unset, a validly-signed token that omits the aud claim is accepted. (A token that carries an aud claim is
still rejected when no expected audience is configured.)
Both options default to unset and have been documented as optional (Importance LOW) since KIP-768 (3.1.0).
Impact:
The exposure is realizable mainly in deployments whose JWKS endpoint serves signing keys for more than one issuer (a multi-tenant identity provider, an aggregated/shared JWKS, or shared signing keys): a token
minted for a different issuer, or a token lacking an audience, may be accepted to authenticate — potentially as a higher-privileged principal. In a single-issuer deployment where the provider controls the iss
claim and issues audience-scoped tokens, exposure is limited. The signature trust anchor remains enforced in all cases. This is distinct from CVE-2026-33557 (acceptance of unsigned/unvalidated tokens); here the
signature is validated and only the issuer/audience checks are not enforced by default.
Mitigation (all affected versions, no upgrade required):
Set both sasl.oauthbearer.expected.issuer (to your provider's exact iss value) and sasl.oauthbearer.expected.audience (to the audience(s) your brokers expect), per listener. Brokers that set these perform
exact-match issuer/audience checks and are not affected. Both have been available since 3.1.0.
Resolution:
- From Apache Kafka 4.4.0: a broker configured with a JWKS endpoint fails to start unless both sasl.oauthbearer.expected.issuer and sasl.oauthbearer.expected.audience are set (secure by default). Deployments that
intentionally do not restrict the issuer and/or audience may opt out per axis with sasl.oauthbearer.allow.unverified.issuer=true and/or sasl.oauthbearer.allow.unverified.audience=true.2d