Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
AV AC PR UI S C I A CVSS EPSS %ile KEV N L N N U H H H 9.8 .8782 99.8 —
AFFECTED Product Versions Fixed OpenSSL Fixed in OpenSSL 1.1.1l (Affected 1.1.1-1.1.1k) – —
TIMELINE Aug 16 Reserved by openssl Aug 24 Published (CNA: openssl) Oct 8 ENRICHED — CVE-2021-3711 (OpenSSL). Received CVSS 9.8 and CPE data from NVD.
In order to decrypt SM2 encrypted data an application is expected to call the API function EVP_PKEY_decrypt(). Typically an application will call this function twice. The first time, on entry, the "out" parameter can be NULL and, on exit, the "outlen" parameter is populated with the buffer size required to hold the decrypted plaintext. The application can then allocate a sufficiently sized buffer and call EVP_PKEY_decrypt() again, but this time passing a non-NULL value for the "out" parameter. A bug in the implementation of the SM2 decryption code means that the calculation of the buffer size required to hold the plaintext returned by the first call to EVP_PKEY_decrypt() can be smaller than the actual size required by the second call. This can lead to a buffer overflow when EVP_PKEY_decrypt() is called by the application a second time with a buffer that is too small. A malicious attacker who is able present SM2 content for decryption to an application could cause attacker chosen data to overflow the buffer by up to a maximum of 62 bytes altering the contents of other data held after the buffer, possibly changing application behaviour or causing the application to crash. The location of the buffer is application dependent but is typically heap allocated. Fixed in OpenSSL 1.1.1l (Affected 1.1.1-1.1.1k).
| Date | Event | Detail |
|---|---|---|
| August 16, 2021 | Reserved | Reserved by openssl |
| August 24, 2021 | Published | Published (CNA: openssl) |
| October 8, 2026 | ENRICHED | ENRICHED — CVE-2021-3711 (OpenSSL). Received CVSS 9.8 and CPE data from NVD. |
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|---|---|---|---|
| OpenSSL | OpenSSL | — | Fixed in OpenSSL 1.1.1l (Affected 1.1.1-1.1.1k) | — |
Authoritative record: CVE-2021-3711 at cve.org
Vendors: openssl
Weaknesses: CWE-120
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2021-3711 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Monday, October 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.
