Security readout for executives and security teams
Plain-English summary
CVE-2025-71402 affects better-auth’s multi-session sign-out handling. A forged multi-session cookie can cause session tokens to be deleted. The likely business impact is forced logouts or session disruption, not confirmed data theft. Public sources rate it low severity, with no KEV listing or cited active exploitation.
Executive priority
Treat as a low-priority but straightforward authentication reliability fix. Patch during the next normal dependency update cycle unless the affected application is high-value or session disruption would materially impact operations.
Technical view
In better-auth versions greater than 1.3.34 and before 1.4.0, the multi-session plugin’s /sign-out after-hook trusts raw _multi-* cookies and passes extracted values to internalAdapter.deleteSessions without verifying the cookie signature. This is CWE-347 improper signature verification and can allow deletion of arbitrary session tokens.
Likely exposure
Exposure is limited to applications using affected better-auth versions with the multi-session plugin and reachable sign-out flow. CVSS indicates network access, low attack complexity, high privileges, user interaction, and prerequisite attack conditions.
Exploitation context
The sources describe forged-cookie session revocation. They do not cite public exploitation, weaponized exploit availability, or CISA KEV inclusion. Expected impact is session invalidation or availability disruption for affected sessions.
Researcher notes
The issue is specifically signature verification failure on multi-session cookies before deleteSessions. Evidence is sufficient for affected-version triage, but the provided sources do not establish active exploitation or broader product impact beyond better-auth.
Mitigation direction
- Upgrade better-auth to version 1.4.0 or later, following vendor guidance.
- Prioritize applications using the multi-session plugin.
- Review authentication flows for unexpected session deletion behavior.
- Monitor vendor advisory updates for additional remediation details.
Validation and detection
- Inventory better-auth versions in package manifests, lockfiles, and SBOMs.
- Confirm whether the multi-session plugin is enabled.
- Identify applications exposing the sign-out flow to authenticated users.
- Review logs for unusual sign-out or session deletion spikes.
- Verify upgraded deployments no longer use affected versions.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-347: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2025-71402 mapping review
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Open ATT&CK lookup- Severity
- Low
- CVSS
- 2 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:L/VI:L/VA:L/SC:L/SI:L/SA:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:L/VI:L/VA:L/SC:L/SI:L/SA:N——VulnCheckVulnerability scoring details
Base CVSS 4.0 score
2LowVector: CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:L/VI:L/VA:L/SC:L/SI:L/SA:N
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- GitHub Security Advisory (GHSA-wmjr-v86c-m9jj)CVE reference, VulnCheck · vendor-advisory
- VulnCheck Advisory: better-auth before 1.4.0 Session Revocation via Forged CookieCVE reference, VulnCheck · third-party-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Verification of Cryptographic Signature
Improper Verification of Cryptographic Signature represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.