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Fencer Vulns
critical 9.8

CVE-2021-3711 in the critical feed json

SM2 Decryption Buffer Overflow

published 2021-08-24 5 y ago modified 2026-10-08 31 d ago also EUVD-2022-2673 , GHSA-5ww6-px42-wc85 , JLSEC-2026-224 , RUSTSEC-2021-0097

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
87.8%
EPSS 87.8% chance of exploitation in 30 days, percentile 99.7%
public exploits
0
none known

Summary

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).

Patch / fix

  • crates.io openssl-src 111.16.0
  • julia OpenSSL_jll 1.1.13+0
  • openssl openssl 1.1.1l
  • oracle essbase 11.1.2.4.47, 21.3
  • oracle jd_edwards_enterpriseone_tools 9.2.6.3
  • openssl Debian 14, Debian 13, Debian 12 1.1.1l-1

debian advisories DEBIAN-CVE-2021-3711

  • openssl Ubuntu 18.04 LTS 1.1.1-1ubuntu2.1~18.04.13
  • openssl Ubuntu 20.04 LTS 1.1.1f-1ubuntu2.8
  • openssl Ubuntu 22.04 LTS 1.1.1l-1ubuntu1
  • openssl Ubuntu Pro FIPS-updates 18.04 LTS 1.1.1-1ubuntu2.fips.2.1~18.04.13.2
  • openssl Ubuntu Pro FIPS-updates 20.04 LTS 1.1.1f-1ubuntu2.fips.7.2

ubuntu advisories UBUNTU-CVE-2021-3711

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • rhnlib Manager Client Tools 15-BETA 5.0.1-159000.6.30.1
  • ansible Manager Client Tools 15-BETA 2.9.27-159000.3.9.1
  • grafana Manager Client Tools 15-BETA 9.5.8-159000.4.24.1
  • mgr-push Manager Client Tools 15-BETA 5.0.1-159000.4.21.1
  • spacecmd Manager Client Tools 15-BETA 5.0.1-159000.6.42.1
  • python-hwdata Manager Client Tools 15-BETA 2.3.5-159000.5.13.1
  • python-pyvmomi Manager Client Tools 15-BETA 6.7.3-159000.3.6.1
  • dracut-saltboot Manager Client Tools Beta for SLE Micro 5, Manager Client Tools 15-BETA 0.1.1681904360.84ef141-159000.3.30.1

suse advisories SUSE-SU-2024:0196-1SUSE-SU-2024:0191-1SUSE-SU-2022:4439-1SUSE-SU-2022:4437-1SUSE-SU-2022:4428-1SUSE-SU-2022:3676-1

  • grype openSUSE Tumbleweed 0.92.1-1.1
  • openssl-1_1 openSUSE Tumbleweed 1.1.1l-1.2
  • grafana openSUSE Tumbleweed 8.3.4-1.1
  • openssl-1_1 openSUSE Leap 15.2 1.1.1d-lp152.7.21.1
  • openssl-1_1 openSUSE Leap 15.3 1.1.1d-11.27.1

opensuse advisories openSUSE-SU-2025:15136-1openSUSE-SU-2024:11127-1openSUSE-SU-2024:11816-1openSUSE-SU-2021:1188-1openSUSE-SU-2021:2830-1

  • openssl Alpine 3.24, Alpine 3.23, Alpine 3.22 +11 more 1.1.1l-r0
  • openssl3 Alpine 3.16, Alpine 3.15 1.1.1l-r0
  • openssl1.1-compat Alpine 3.18, Alpine 3.17 1.1.1l-r0

alpine advisories ALPINE-CVE-2021-3711

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • openssl CBL-Mariner 2.0 1.1.1k-11

azure linux advisories AZL-6779

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

  • openssl Arch Linux 1.1.1.l-1
  • lib32-openssl Arch Linux 1:1.1.1.l-1

arch linux advisories AVG-2315AVG-2316

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-3711 updated cvss 9.8

openssl: SM2 Decryption Buffer Overflow

  • Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/management-ingress-rhel8
    affected: no fix available
  • Red Hat Enterprise Linux 6 openssl, openssl098e, openssl-perl Red Hat Enterprise Linux 7 openssl, openssl098e, openssl-libs, openssl-perl Red Hat Enterprise Linux 8 openssl, openssl-libs, openssl-perl, compat-openssl10 Red Hat Enterprise Linux 9 openssl, openssl-libs, openssl-perl Red Hat JBoss Core Services jbcs-httpd24-openssl Red Hat JBoss Web Server 3 openssl
    +2 more products
    Red Hat JBoss Web Server 5 openssl Red Hat Virtualization 4 redhat-virtualization-host-image-update
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-25-226-21 updated cvss 9.8

Siemens BFCClient

  • Siemens BFCClient < 2.17
    affected: fixed in V2.17

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

cisa ICSA-23-143-02 updated cvss 9.8

Hitachi Energy's RTU500 Series Product (UPDATE B)

  • Hitachi Energy RTU500 series CMU Firmware >=12.0.1, <=12.0.15, >=12.2.1, <=12.2.12, >=12.4.1, <=12.4.12, >=12.6.1, <=12.6.9
    affected: vendor fix, mitigation “Hitachi Energy has released the following mitigations/fixes for CVE-2022-23937, CVE-2022-0778, CVE-2021-3711, and CVE-2021-3712:” search.abb.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

cisa ICSA-22-342-02 updated cvss 9.8

AVEVA InTouch Access Anywhere and Plant SCADA Access Anywhere

  • AVEVA Software, LLC InTouch Access Anywhere <= 2023 AVEVA Software, LLC Plant SCADA Access Anywhere <= 2020 R2
    affected: mitigation “InTouch Access Anywhere Secure Gateway 2020 R2 (version 20.1.0) Hotfix.”

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

cisa ICSA-22-132-02 updated cvss 9.8

Mitsubishi Electric MELSOFT iQ AppPortal

  • Mitsubishi Electric MELSOFT iQ AppPortal (SW1DND-IQAPL-M) >= 1.00A, <= 1.26C
    affected: mitigation “Update to 1.29F or later. Unzip the downloaded file (zip format) and execute the file “setup.exe.”” mitsubishielectric.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
31 d ago

Exploit prediction

87.82% chance of exploitation in the next 30 days, higher than 99.7% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
GitHub 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P
OSV 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
crates.io openssl-src
<111.16.0
>=0.0.0-0, <111.16.0
111.16.0
julia OpenSSL_jll
<1.1.13+0
1.1.13+0

Affected products

  • OpenSSL OpenSSL

Classification

Weakness
  • CWE-120 Buffer Copy without Checking Size of Input
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.