CVE-2026-63132: OpenBao's Recovery Mode Vulnerable To Token Leakage via Timing Attack

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.5%, percentile 42: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 42% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes github.com/openbao/openbao (Go) < 0.0.0-20260713141742-763625a20721, fixed in 0.0.0-20260713141742-763625a20721; github.com/openbao/openbao (Go) >= 0.1.0, <= 1.1.5, no fixed version listed. Check your lockfile, including transitive dependencies.

What it is

OpenBao is an open source identity-based secrets management system. Prior to 2.6.0, OpenBao's handleLogicalRecovery path in http/logical.go compared the highly privileged recovery token with ordinary string equality. A remote unauthenticated attacker able to make repeated recovery mode requests and measure response timing could infer the recovery token. The recovered token could then authorize recovery mode operations that read or modify OpenBao data. This issue is fixed in version 2.6.0.

From the GitHub advisory

Impact

When running in the highly privileged recovery mode, OpenBao was vulnerable to a timing attack against the single recovery token. This allowed an attacker to extract the recovery token and use it to perform operations against the OpenBao instance, including reading or modification of data.

Patches

This has been patched in OpenBao v2.6.0.

Weakness type: CWE-208.

Product: github.com/openbao/openbao (Go) · Assigned by: GitHub_M · Published: 2026-09-23

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: high (needs special conditions)
• Attack requirements: present (depends on deployment conditions)
• Privileges required: none (no login)
• User interaction: none

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.50% probability of exploitation activity in the next 30 days; percentile 42.

Timeline

• 2026-09-22 — GitHub-reviewed advisory GHSA-34fc-gh42-pj53 published (critical)
• 2026-09-23 — CVE record last updated
• 2026-09-23 — CVE record published by GitHub_M

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-34fc-gh42-pj53 github.com
2. CVE.org record CVE-2026-63132 cve.org
3. NVD entry CVE-2026-63132 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
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3. github.com github.com
4. github.com github.com
5. github.com github.com
6. github.com github.com
7. github.com github.com

Critical Go advisories · Today’s Security Digest