CVE WatchSep 6, 2026

CVE-2026-86219

Authen::SASL::Perl::DIGEST_MD5 versions before 2.2100 for Perl accept replayed authentication responses via unverified nonce in server_step.

CVSS

—

No CVSS

EPSS

—

KEV

—

Exploit Today

—

0-100

Published: Sep 6, 2026 · Last modified: Sep 6, 2026 · CWE-294

EPSS · 30d

Not enough EPSS history yet.

Technical description

Authen::SASL::Perl::DIGEST_MD5 versions before 2.2100 for Perl accept replayed authentication responses via unverified nonce in server_step. server_start generates a fresh nonce and sends it in the challenge, and nothing later compares that value against the nonce the client returns. server_step derives the expected digest from the client's own parameters, so a response verifies whenever its digest matches the nonce it carries. The count table it also checks is keyed on the client-supplied nonce and starts empty in each new server object, so a captured first response, carrying `nc=00000001`, passes that too. RFC 2831 defines the nonce in the response as the value the server sent in the preceding challenge. An attacker who observes one successful `qop=auth` exchange can replay the captured response against a later session for the same service, host, realm and user, and authenticate as that user without knowing the password.

Official references

Related CVEs

CVECVSSEPSSKEVRExploitTitleMod.

CVE-2026-750347.4 HIG

9.5%

——3A flaw was found in Rancher Manager. The SAML assertion replay protection introduced by the fix for CVE-2026-44946 recorded consumed assertion IDs in a per-process cache, so each replica only detected replays that reached the same pod. In a high-availability deployment, an attacker holding a captured assertion could replay it once against every other replica to obtain additional authenticated sessions as the victim. This issue affects Rancher: before 2.15.1.3d CVE-2026-536364.7 MED

6.9%

——2Open edX Platform enables the authoring and delivery of online learning at any scale. Prior to commit 3a5ac85, a security vulnerability has been identified in the Open edX LMS platform's LTI (Learning Tools Interoperability) Provider implementation. The validate_timestamp_and_nonce function in lms/djangoapps/lti_provider/signature_validator.py does not validate OAuth nonces or timestamps, allowing an attacker who captures a valid LTI launch request to replay it an unlimited number of times without detection. This issue has been patched via commit 3a5ac85.4d CVE-2026-127046.8 MED

19.4%

——6When SAML IdP-initiated login is enabled in Grafana Enterprise, the SAML library skips validation of the InResponseTo field on all SAML responses, including SP-initiated logins. This removes anti-replay protection, allowing an attacker who obtains a valid signed SAML assertion to replay it and gain a session as the victim user. Only instances with the allow_idp_initiated SAML setting enabled are affected; this setting is off by default and Grafana OSS is not affected.3d CVE-2026-843066.5 MED

29.2%

——9Filament is a collection of full-stack components for accelerated Laravel development. From 4.0.0 until 4.12.6 and 5.7.6, packages/panels/src/Auth/MultiFactor/App/AppAuthentication.php uses AppAuthentication::verifyCode() with a used-code cache key derived from both the app authentication secret and the submitted TOTP code. This isolates the newest accepted timestep by code instead of by secret, allowing a previously issued app-based MFA code to be accepted after a newer code has already been used. Reuse of the exact same code was already prevented, but another code inside the accepted time window remained usable. An attacker who obtains the target account's password and one app-based MFA code can use that code for the remainder of the configured window, which is approximately four minutes with the default settings, even after the legitimate account holder logs in with a newer code. Email-based MFA is not affected. This issue is fixed in versions 4.12.6 and 5.7.6.3d CVE-2026-824705.4 MED

14.3%

——4Rodauth before 2.47.0 contains a time-based one-time password reuse vulnerability in the otp feature that fails to track the last accepted code timestamp. Attackers who observe a valid TOTP code can replay it during the drift window to bypass the second authentication factor.8d CVE-2026-137346.5 MED

16.0%

——5Zephyr's WireGuard VPN data-plane receive handler wg_process_data_message() in subsys/net/lib/wireguard/wg_crypto.c validated the anti-replay counter too late. After AEAD decryption of a MESSAGE_TRANSPORT_DATA packet succeeded, the code committed several peer-state changes — update_peer_addr() (endpoint roaming update), the keypair->last_rx/peer->last_rx liveness timers, and keypair_update() (promote next→current and destroy the previous keypair) — and only afterward called wg_check_replay(). On a replayed packet the replay check returned -EINVAL, but none of the preceding mutations were rolled back. The AEAD tag authenticates content but not freshness, so a replayed-but-authentic transport packet decrypts correctly. An attacker who captures one valid ciphertext off the wire (an on-path or shared-medium observer) can re-inject it from an arbitrary spoofed source address. Reaching the handler requires no credentials: it is driven directly from inbound UDP datagrams via the dispatch in subsys/net/lib/wireguard/wg.c. Because the state mutations committed before the replay check, the replay repoints the peer endpoint to the attacker-chosen source address (roaming hijack), redirecting the victim's subsequent outbound tunnel traffic until the legitimate peer's next packet re-corrects it; it also prematurely destroys the previous keypair and refreshes the RX liveness timer. The tunnel payload stays encrypted under the session keypair, so this is an integrity/availability impact (traffic redirection and session disruption), not payload disclosure. The fix moves wg_check_replay() to immediately after a successful decrypt, before any peer-state mutation, matching the WireGuard specification and the Linux reference implementation.5d