CVE-2026-32877 | Botan: Heap Buffer Over-read in SM2 Decryption via Undersized C3 Hash Field

Botan is a C++ cryptography library. From version 2.3.0 to before version 3.11.0, during SM2 decryption, the code that checked the authentication code value (C3) failed to check that the encoded value was of the expected length prior to comparison. An invalid ciphertext can cause a heap over-read of up to 31 bytes, resulting in a crash or potentially other undefined behavior. This issue has been patched in version 3.11.0.

Published: 2026-03-30 Last update: 2026-04-13 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-32877 is rated Low Risk (39.8/100): CVSS High severity, with low exploitation likelihood (EPSS 0.28%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

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

Exploit prediction scoring system (EPSS) score for CVE-2026-32877

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 2026-06-15 0.05% 0.28% +0.22%
2 2026-04-05 0.04% 0.05% +0.01%
3 2026-03-31 — 0.04% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-32877

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.2 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
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:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
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.
 3.9 4.2 [email protected]
8.2 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
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:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
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.
 3.9 4.2 [email protected]

Weakness enumeration for CVE-2026-32877

OS Trackers for CVE-2026-32877

vendor priority summary link
alpine — CVE-2026-32877: 1 source package rows (botan); 32 state rows across 4 repos (3.19-main, 3.20-main, 3.21-main, edge-main); fixed 0, open 32. https://security.alpinelinux.org/vuln/CVE-2026-32877
debian not yet assigned CVE-2026-32877 not yet assigned priority: Debian including 2 source packages (botan, botan3), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 4, resolved 2. https://security-tracker.debian.org/tracker/CVE-2026-32877
redhat medium — https://access.redhat.com/security/cve/CVE-2026-32877
ubuntu medium CVE-2026-32877 medium priority: Ubuntu including 3 source packages (botan, botan1.10, botan3), 17 status rows across 8 suites (bionic, focal, jammy, noble, questing, trusty, upstream, xenial): needs-triage 12, DNE 5. https://ubuntu.com/security/CVE-2026-32877

Affected software / configurations for CVE-2026-32877

Vendor Product Version Raw CPE
botan_project botan >= 2.3.0, < 3.11.0 cpe:2.3:a:botan_project:botan:*:*:*:*:*:*:*:*

References for CVE-2026-32877

cvelogic Threat Intelligence