Authentication Bypass by Capture-replay

A flaw was found in Keycloak. When deployed in stateless mode with MySQL or MariaDB, a mismatch in row-count semantics between the database driver and Keycloak's application logic allows an attacker to bypass replay protection. This vulnerability enables an attacker who intercepts single-use security artifacts, such as JWT client assertions, DPoP proofs, or one-time password (TOTP) codes, to replay them. Successful exploitation grants unauthorized access to the token endpoint or login flow.Show less

On affected platforms running Arista EOS with VRRPv2 IP-AH authentication configured, an unauthenticated attacker within the same layer 2 network segment on which VRRP is running can capture a legitimate authenticated VRRP advertisement and replay it indefinitely. Replayed advertisements can be used to advertise stale VRRP state, for example to prevent a backup router from taking over the virtual gateway after the original master has gone down, resulting in a denial of service for hosts using the virtual gateway address.Show less

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, DigestAuth replay protection records lastNc plus one instead of the highest nonce-count value it has accepted. When a legitimate client sends noncontiguous nc values because of parallel or retried requests, the stored counter remains below the accepted maximum, allowing a passive observer to replay a captured Authorization header multiple times. Successful replays execute authenticated requests, including state-changing operations, as the captured user. This issue is fixed in versions 0.23.35 and 1.0.0-M47.Show less

Maravel, a PHP framework oriented towards dependency injection, prior to version 10.74.0 has a high-severity Token Replay Vulnerability arising from a structural lifecycle mismatch between stateless token validation engines and high-performance relational caching layers. Any application with low cache memory that causes premature eviction to free up memory and applications running macropay-solutions/maravel-framework that utilize tymon/jwt-auth for API token authentication and blacklist management or any other package that does the same may be affected. This architectural risk might also impact native Laravel applications utilizing cache tags under specific volatile or eviction-capped environments. tymon/jwt-auth automatically probes for cache tag support. If found, it forcefully wraps 14-day token blacklist entries (jti) inside a relational tymon.jwt tag. In environments where the O(1) Atomic Lazy Eviction model is active — either natively inside Maravel-Framework v20.x or manually backported into v10.x via the explicit DI container singletons provided in PR #104 (App\Cache\TaggedCache and App\Cache\TagSet) — a strict global tracking ceiling (Container::TAGGED_CACHE_TTL_CAP_SECONDS) of 7,200 seconds (2 hours) is enforced to secure the system against memory index bloat. This ceiling forcefully truncates the 14-day blacklist lifespan down to a maximum of 2 hours, after which individual tracking keys naturally expire and disappear from the active cache window. Furthermore, because the optimized engine implements a generational version matrix to achieve O(1) flush speeds, any programmatic or manual invocation of a tag flush or reset (e.g., Cache::tags([...])->flush()) instantly bumps the internal atomic master version pointer. This shifts the computed cryptographic composite hash (sha1($this->tags->getNamespace())) for all overlapping components, rendering the entire existing index immediately unreachable. Consequently, through either natural 2-hour expiration or an intervening tag flush execution (like the cache naturally cleaning old values to free up memory), the invalidation state records are entirely wiped out. Because the tokens' physical cryptographic signatures remain structurally valid for up to 14 days, stolen, hijacked, or legitimately logged-out tokens are instantly and silently resurrected across the entire API gateway, leaving the application critically vulnerable to widespread Token Replay Attacks. Because this issue is caused by an upstream architectural assumption within the tymon/jwt-auth package rather than a core defect inside the framework, there is no direct framework version upgrade that can safely bypass this lifecycle collision without breaking business cache recycling bounds. Maravel version 10.74.0 introduced a way to backport the new fixed tagged cache from 20.x into 10.x by resolving TagSet and TaggedCache from DI, which is how this latent architectural lifecycle vulnerability was discovered. Users must apply the decoupled configuration workaround outlined below. As a workaround, make sure that cache memory size does not generate early natural evictions from cache to free up space, deleting blacklisted jwt ids before they expire. Applications must decouple flat authentication vectors from the relational tagging subsystem. This forces token identifiers to write directly to the primary cache keyspace as flat, un-tagged key-value pairs where they securely retain their unclipped 14-day lifecycle.Show less

XenForo before 2.3.13 contains a refresh token replay vulnerability that allows attackers to reuse a refresh token multiple times by exploiting the failure to mark tokens as consumed when the parent access token has expired. Attackers can repeatedly submit the same refresh token to generate additional independent token pairs, achieving persistent unauthorized access for the token's full lifetime.Show less

XenForo before 2.3.13 contains an OAuth2 authorization code reuse vulnerability that allows attackers to obtain unauthorized token pairs by submitting a previously used authorization code. Attackers can exploit the failure to invalidate or mark authorization codes as consumed after initial token issuance to receive an independent token pair for the same user and scopes, bypassing the single-use guarantee of the OAuth2 authorization code flow.Show less

PocketMine-MP 3.x (before 3.27.0) does not implement Minecraft Bedrock protocol encryption, so the server cannot verify that a connecting client possesses the private key corresponding to its login token. An attacker who captures a valid login from another player's session (for example by tricking the player into connecting to an attacker-controlled server) can replay that login to impersonate the victim and pass XBOX Live authentication until the JWT token expires (typically 2-3 days). This affects servers directly reachable over the internet that are not behind a proxy with encryption enabled. Fixed in 4.0.0 and backported to 3.27.0.Show less

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.Show less

A 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.Show less

Open 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.Show less

When 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.Show less

Filament 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.Show less

Rodauth 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.Show less

Zephyr'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.Show less

An issue in Vanderbilt Industries, Acre Security SPC5300.000 Main Board v.3.14.1 allows a physically proximate attacker to cause a denial of service via spoofed TCP FIN packets without validating the sequence or acknowledgment numbers.Show less

An issue in Vanderbilt Industries, Acre Security SPC5300.000 Main Board v.3.14.1 allows a physically proximate attacker to cause a denial of service via the SPC Connect Pro software accepts replayed application-layer payloads injected into an active TCP session.Show less