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Fencer Vulns
critical 9.1

CVE-2021-46848 json

GNU Libtasn1 before 4.19.0 has an ETYPE_OK off-by-one array size check that affects asn1_encode_simple_der.

published 2022-10-24 4 y ago modified 2026-10-14 26 d ago also EUVD-2021-33503

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.8%
EPSS 2.8% chance of exploitation in 30 days, percentile 86%
public exploits
0
none known

Summary

GNU Libtasn1 before 4.19.0 has an ETYPE_OK off-by-one array size check that affects asn1_encode_simple_der.

Patch / fix

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP V3.1.5
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • libtasn1-6 Debian 14, Debian 13, Debian 12 4.19.0-2

debian advisories DEBIAN-CVE-2021-46848

  • libtasn1-6 Ubuntu 22.04 LTS 4.18.0-4ubuntu0.2
  • libtasn1-6 Ubuntu Pro 14.04 LTS 3.4-3ubuntu0.6+esm1
  • libtasn1-6 Ubuntu Pro 16.04 LTS 4.7-3ubuntu0.16.04.3+esm3
  • libtasn1-6 Ubuntu Pro 18.04 LTS 4.13-2ubuntu0.1~esm1
  • libtasn1-6 Ubuntu Pro 20.04 LTS 4.16.0-2ubuntu0.1+esm1

ubuntu advisories UBUNTU-CVE-2021-46848

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

  • libtasn1 RHEL 9 4.16.0-8.el9_1
  • libtasn1-tools RHEL 9 4.16.0-8.el9_1
  • libtasn1 RHEL 8 4.13-4.el8_7
  • libtasn1-tools RHEL 8 4.13-4.el8_7
  • libtasn1 RHEL 8.6 EUS 4.13-3.el8_6.1
  • libtasn1-tools RHEL 8.6 EUS 4.13-3.el8_6.1

red hat advisories RHSA-2024:0427RHSA-2023:0343RHSA-2023:0116

  • libtasn1 SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES 12 SP5 +5 more 4.9-3.13.1
  • libtasn1 SLES 12 SP2-BCL 3.7-13.7.1
  • libtasn1 SLES for SAP 15 SP2, SLES for SAP 15 SP1, SLES for SAP 15 +24 more 4.13-150000.4.8.1

suse advisories SUSE-SU-2022:3817-1SUSE-SU-2022:3797-1SUSE-SU-2022:3784-1

  • libtasn1 AlmaLinux 9 4.16.0-8.el9_1
  • libtasn1-tools AlmaLinux 9 4.16.0-8.el9_1
  • libtasn1 AlmaLinux 8 4.13-4.el8_7
  • libtasn1-tools AlmaLinux 8 4.13-4.el8_7

almalinux advisories ALSA-2023:0343ALSA-2023:0116

  • libtasn1 Rocky Linux 9 4.16.0-8.el9_1
  • libtasn1 Rocky Linux 8 4.13-4.el8_7

rocky linux advisories RLSA-2023:0343RLSA-2023:0116

  • libtasn1 Alpine 3.14 4.17.0-r1
  • libtasn1 Alpine 3.16, Alpine 3.15 4.18.0-r1
  • libtasn1 Alpine 3.24, Alpine 3.23, Alpine 3.22 +5 more 4.19-r0

alpine advisories ALPINE-CVE-2021-46848

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

  • libtasn1 CBL-Mariner 2.0 4.19.0-1

azure linux advisories AZL-11318

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

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-2021-46848 updated cvss 5.9

libtasn1: Out-of-bound access in ETYPE_OK

  • Red Hat Enterprise Linux 7 libtasn1, libtasn1-tools
    affected: no fix planned “Out of support scope”
  • Red Hat Satellite 6 libtasn1
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux AppStream (v. 8) libtasn1-tools 4.13-4.el8_7
    fixed: vendor fix RHSA-2023:0116
  • Red Hat Enterprise Linux AppStream (v. 9) libtasn1-tools 4.16.0-8.el9_1
    fixed: vendor fix RHSA-2023:0343
  • Red Hat Enterprise Linux AppStream EUS (v.8.6) libtasn1-tools 4.13-3.el8_6.1
    fixed: vendor fix RHSA-2024:0427
  • Red Hat Enterprise Linux BaseOS (v. 8) libtasn1 4.13-4.el8_7
    fixed: vendor fix RHSA-2023:0116
  • Red Hat Enterprise Linux BaseOS (v. 9) libtasn1 4.16.0-8.el9_1
    fixed: vendor fix RHSA-2023:0343
  • Red Hat Enterprise Linux BaseOS EUS (v.8.6) libtasn1 4.13-3.el8_6.1
    fixed: vendor fix RHSA-2024:0427
show 1 more
  • Red Hat Enterprise Linux 6 libtasn1, libtasn1-tools
    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-23-348-10 updated cvss 9.1

Siemens SIMATIC S7-1500

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.0, < 3.1.5
    affected: fixed in V3.1.5, mitigation support.industry.siemens.com

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

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
18 mo ago

Exploit prediction

2.82% chance of exploitation in the next 30 days, higher than 86% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • gitlab.com https://gitlab.com/gnutls/libtasn1/-/issues/32 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
NVD 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Affected products

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

Classification

Weakness

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.