CVE-2021-41581

Exp

x509_constraints_parse_mailbox in lib/libcrypto/x509/x509_constraints.c in LibreSSL through 3.4.0 has a stack-based buffer over-read. When the input exceeds DOMAIN_PART_MAX_LEN, the buffer lacks '\0' termination.

Published: 2021-09-24 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-41581 is rated Exploit Available (55.8/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.30%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-41581

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-41581

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-11-21 0.15% 0.30% +0.15%
2 2025-11-18 0.26% 0.15% -0.11%
3 2025-03-17 — 0.26% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-41581

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2021-41581

OS Trackers for CVE-2021-41581

vendor priority summary link
alpine medium CVE-2021-41581: 1 source package rows (libressl); 8 state rows across 4 repos (3.11-main, 3.12-main, 3.22-community, edge-community); fixed 0, open 8. https://security.alpinelinux.org/vuln/CVE-2021-41581

Affected software / configurations for CVE-2021-41581

Vendor Product Version Raw CPE
openbsd libressl <= 3.4.0 cpe:2.3:a:openbsd:libressl:*:*:*:*:*:*:*:*

References for CVE-2021-41581

URL Tags
https://github.com/libressl-portable/openbsd/issues/126 Exploit Issue Tracking Patch Third Party Advisory
cvelogic Threat Intelligence