CVE-2025-11931Network attack vectorHinoki check available

Out-of-bounds access via unchecked negative decrypt length

Published Nov 21, 2025 · Updated Nov 21, 2025

Integer underflow in wolfSSL before 5.8.4 allows attackers to trigger out-of-bounds access through direct decryption API calls. wc_XChaCha20Poly1305_crypt_oneshot fails to reject a negative dst_len before buffer access, allowing the signed length calculation to underflow. The flaw is unreachable through TLS and requires an application to call wc_XChaCha20Poly1305_Decrypt on attacker-influenced input; reported effects are limited to low-impact data exposure or modification.

CVSS severity2.1
Low
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Integer underflow in wolfSSL before 5.8.4 allows attackers to trigger out-of-bounds access through direct decryption API calls. wc_XChaCha20Poly1305_crypt_oneshot fails to reject a negative dst_len before buffer access, allowing the signed length calculation to underflow. The flaw is unreachable through TLS and requires an application to call wc_XChaCha20Poly1305_Decrypt on attacker-influenced input; reported effects are limited to low-impact data exposure or modification.

The record

CVE
CVE-2025-11931
Published
Nov 21, 2025
Updated
Nov 21, 2025
Vendor
wolfSSL
Product
wolfSSL
Classifications
CWE-191
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 21, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 21, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.8.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

wolfSSL · wolfSSLversion=5.8.4

Published CVSS scores

2.1wolfSSL Inc.CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
8.2NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-191Integer Underflow (Wrap or Wraparound)

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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