CVE-2025-52893: OpenBao Information Disclosure Vulnerability

CVE-2025-52893 Overview

CVE-2025-52893 is an information disclosure vulnerability in OpenBao, an open-source secrets management platform used to store and distribute certificates, keys, and other sensitive data. Versions before v2.3.0 may leak sensitive values in error logs when the sdk/framework processes malformed request data. The issue is distinct from the earlier HCSEC-2025-09 (CVE-2025-4166) disclosure that affected HashiCorp Vault's kv-v2 plugin. The root cause resides in the upstream go-viper/mapstructure library, which included user-supplied values in ParseError messages. Authenticated clients submitting malformed input can cause secret material embedded in requests to appear in operator-accessible logs.

Critical Impact
Sensitive values submitted in malformed requests can be written to OpenBao error logs, exposing secrets to anyone with log access.

Affected Products

OpenBao versions prior to v2.3.0
Deployments relying on the sdk/framework request parsing path
Environments using the vulnerable go-viper/mapstructure dependency

Discovery Timeline

2025-06-25 - CVE-2025-52893 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-52893

Vulnerability Analysis

The vulnerability is an information exposure through log files [CWE-532]. When OpenBao's sdk/framework decodes an incoming request, it delegates type conversion to the mapstructure library. If a field fails to parse into the expected type, mapstructure constructs a ParseError that embeds the raw offending value directly in the error string. OpenBao then logs this error at the server level. Because request bodies frequently carry secret material such as tokens, credentials, or key data, a malformed submission causes that material to be written to persistent logs. Any operator, log-aggregation pipeline, or downstream system with log access can subsequently read the exposed value. Exploitation requires an authenticated client and a user-interaction condition on the malformed request path, which limits the attacker profile but does not eliminate risk in multi-tenant deployments.

Root Cause

The defect lives in mapstructure's ParseError.Error() method, which formatted the string cannot parse '%s' as '%s': %s using the untrusted e.Value. Any caller logging the error surfaced the raw input in cleartext.

Attack Vector

An authenticated user submits a request whose payload is deliberately malformed so that a field expected to be a specific type (for example integer or duration) contains a sensitive string. OpenBao's framework attempts to decode the field, mapstructure returns a ParseError containing the raw value, and OpenBao writes the error to its log stream.

// Upstream patch in go-viper/mapstructure errors.go
func (e *ParseError) Error() string {
-	return fmt.Sprintf("cannot parse '%s' as '%s': %s", e.Value, e.Expected.Type(), e.Err)
+	return fmt.Sprintf("cannot parse value as '%s': %s", e.Expected.Type(), e.Err)
}

func (*ParseError) mapstructure() {}

Source: go-viper/mapstructure commit ed3f921. The fix removes e.Value from the emitted error string so that malformed input can no longer leak into logs.

Detection Methods for CVE-2025-52893

Indicators of Compromise

Log entries in OpenBao server logs containing the substring cannot parse ' followed by request-derived content.
Error messages referencing ParseError or mapstructure type conversion failures.
Unusual concentrations of parse errors from a single authenticated identity or API token.

Detection Strategies

Grep OpenBao and container logs for the pre-patch error format cannot parse '<value>' as to identify historical exposures.
Correlate ParseError occurrences with the authenticated caller and endpoint to identify requests that may have leaked secret material.
Compare deployed OpenBao binary versions against v2.3.0 across the fleet using package or image inventory data.

Monitoring Recommendations

Forward OpenBao server logs to a centralized platform and apply pattern matching for mapstructure parse failures.
Alert on new occurrences of the vulnerable error signature after upgrade to detect regressions or unpatched instances.
Review log-retention and access-control settings so that log stores holding potentially exposed secrets follow the same access model as OpenBao itself.

How to Mitigate CVE-2025-52893

Immediate Actions Required

Upgrade OpenBao to v2.3.0 or later, which includes the upstream mapstructure fix and the sdk/framework hardening tracked in changelog entry 1495.txt.
Rotate any secrets, tokens, or keys that may have appeared in prior log entries generated by malformed requests.
Restrict access to historical OpenBao log archives and purge entries containing the vulnerable error signature after review.

Patch Information

The fix is delivered in OpenBao commit cf5e920badbf96b41253534a3fd5ff5063bf4b30 and released in v2.3.0. The upstream dependency fix is go-viper/mapstructure release v2.3.0. See the OpenBAO Security Advisory GHSA-8f5r-8cmq-7fmq for full advisory text and the OpenBAO commit note for the changelog entry:

text

+```release-note:security
+sdk/framework: prevent additional information disclosure on invalid request. CVE-2025-52893.
+```

Workarounds

No configuration-based workaround exists. Ensure all clients submit properly formatted requests to avoid triggering the vulnerable error path.
Reduce OpenBao server log verbosity where operationally acceptable and tighten log-store access controls until the upgrade is complete.

bash

# Verify installed OpenBao version and upgrade
bao version
# Upgrade to a fixed release
apt-get update && apt-get install --only-upgrade openbao=2.3.0
# Confirm the fixed version is running
bao version | grep -E 'v2\.(3|[4-9])'