Security Resilience

CVE-2026-73683

Auth Bypass

Public PoCAuth Bypass
Published
14 August 2026
Modified
24 September 2026
CVSS Score v4 9.2
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0076 55th percentile
Risk Priority 38 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). EPSS, Forum of Incident Response and Security Teams (FIRST), epss.first.org. Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-73683 is a critical-severity Authentication Bypass by Capture-replay (CWE-294) vulnerability. Its CVSS base score is 9.2 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Valid Accounts (T1078); ranked in the top 45% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SC-23 (Session Authenticity) and SC-8 (Transmission Confidentiality and Integrity) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A07:2025 Authentication Failures

EU & UK References

Vulnerability Data

Laravel Socialite's Facebook provider contains an authentication bypass vulnerability that allows unauthenticated attackers to replay captured OIDC id_tokens by exploiting the missing nonce claim validation in the getUserByOIDCToken() function within FacebookProvider.php. Attackers who obtain a valid, unexpired id_token issued for…

more

the same Facebook App ID can submit the captured token to the backend userFromToken() endpoint, bypassing authentication controls because signature, aud, and iss checks pass while no session-bound nonce comparison is performed, resulting in unauthorized access to victim accounts.

CWE(s)
CWE-294

Related Threats

MITRE ATT&CK Enterprise Techniques

MITRE ATT&CK v20.0

T1078 Valid Accounts Stealth
Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
T1550 Use Alternate Authentication Material Lateral Movement
Adversaries may use alternate authentication material, such as password hashes, Kerberos tickets, and application access tokens, in order to move laterally within an environment and bypass normal system access controls.
attack.mitre.org →
T1550.002 Pass the Hash Lateral Movement
Adversaries may “pass the hash” using stolen password hashes to move laterally within an environment, bypassing normal system access controls.
attack.mitre.org →
T1550.003 Pass the Ticket Lateral Movement
Adversaries may “pass the ticket” using stolen Kerberos tickets to move laterally within an environment, bypassing normal system access controls.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-73136Shared CWE-294
CVE-2026-73431Shared CWE-294
CVE-2024-3982Shared CWE-294
CVE-2023-34553Shared CWE-294
CVE-2026-41020Shared CWE-294
CVE-2023-50128Shared CWE-294
CVE-2025-13777Shared CWE-294
CVE-2023-45794Shared CWE-294
CVE-2024-39081Shared CWE-294
CVE-2025-26201Shared CWE-294

Affected Assets

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V10.4.16
  • V10.5.1

Mitigating Controls (NIST 800-53 r5)

Our mappings, made for this CVE.

SC-23 Session Authenticity good match

Session authenticity mechanisms directly stop replay of captured authentication traffic by enforcing freshness or cryptographic binding.

SC-8 Transmission Confidentiality and Integrity good match

Transmission integrity (with anti-replay) stops captured messages from being accepted as valid later.

Mitigating Controls (NIST CSF 2.0)

Our mappings, derived directly from the weakness types (CWEs) cited in the NVD entry via our CWE→CSF cross-walk — links open the control.

PR.AA-04 mostly match
blocks

Protecting and verifying identity assertions prevents replay of captured authentication material.

PR.DS-02 mostly match
blocks

Encryption and integrity protections for data-in-transit directly block capture-replay of credentials or tokens.

DE.CM-01 partial match
blocks

Network monitoring may detect anomalous replays after the fact but does not prevent the design flaw.

PR.AA-03 partial match
blocks

Strong authentication methods can reduce replay risk but do not inherently address captured messages.

Mitigating Controls (ISO/IEC 27001:2022 Annex A)

Our mappings, derived directly from the weakness types (CWEs) cited in the NVD entry via our CWE→ISO cross-walk — links open the control.

A.8.24 Use of cryptography mostly match
blocks

Cryptographic protections (e.g., nonces, timestamps, message authentication codes) make captured authentication messages unusable for replay.

A.8.28 Secure coding partial match
prevents

A.8.28's secure design/architecture and threat modelling guidance (planning item g) and its prohibition on insecure design techniques can catch capture-replay during design, but the clause mandates a fallible practice whose effect depends on developer rigour, so only a minority of instances are prevented.

A.8.5 Secure authentication partial match
blocks

A.8.5 addresses several vectors relevant to capture-replay: item (j) bars cleartext password transmission, items (k) and (l) shorten the window via session termination and connection-duration limits, and the strong-authentication and MFA guidance (certificates, smart cards, tokens) typically carries replay protection as part of those mechanisms. But the clause does not mandate anti-replay primitives (nonces, timestamps, challenge-response) at the protocol level, and for non-critical systems password-only authentication remains acceptable, so a system compliant with A.8.5 can still be vulnerable to capture-replay — the remainder is nameable and not bounded to a vanishing slice.

A.8.8 Management of technical vulnerabilities partial match
finds

A.8.8's reach is DISCLOSURE-based, and CWE-294 does surface as CVEs (observed examples include CVE-2005-3435 and CVE-2007-4961), so vulnerability scanning, advisory tracking, and external reports will surface some instances; the disclosed share of any weakness class is a minority, capping the rung at `partial`.

References