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Fencer Vulns
high 8.1

CVE-2026-7383 json

Possible Heap Buffer Overflow in ASN.1 Multibyte String Conversion

published 2026-06-09 5 mo ago modified 2026-08-13 2 mo ago also EUVD-2026-35474 , GHSA-w853-v86g-gv7j , JLSEC-2026-1155

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 56%
public exploits
0
none known

Summary

Issue summary: A signed integer overflow when sizing the destination buffer for Unicode output in ASN1_mbstring_ncopy() can lead to a heap buffer overflow.

Impact summary: A heap buffer overflow may lead to a crash or possibly attacker controlled code execution or other undefined behaviour.

In ASN1_mbstring_copy() and ASN1_mbstring_ncopy() the destination size for Unicode output is computed in a signed int: by left shift of the input character count for BMPSTRING (UTF-16) and UNIVERSALSTRING (UTF-32), and by summing per-character byte counts for UTF8STRING. The calculation overflows when the input reaches around 2^30 characters. In the worst case (UNIVERSALSTRING at 2^30 characters) the size wraps to zero, OPENSSL_malloc(1) is called, and the subsequent character copy writes several gigabytes past the one-byte allocation.

X.509 certificate processing routes through ASN1_STRING_set_by_NID(), whose DIRSTRING_TYPE mask excludes UNIVERSALSTRING and whose per-NID size limits cap the input length; no network protocol or certificate-handling path in OpenSSL exercises the overflow. Triggering the bug requires an application that calls ASN1_mbstring_copy() or ASN1_mbstring_ncopy() directly, or registers a custom string type via ASN1_STRING_TABLE_add(), with attacker-controlled input on the order of half a gigabyte or more. For these reasons this issue was assigned Low severity.

The FIPS modules in 4.0, 3.6, 3.5, 3.4 and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.

Patch / fix

  • julia AppBundler 1.0.1
  • julia OpenSSL_jll 3.5.7+0
  • OpenSSL OpenSSL 1.0.2zq, 1.1.1zh, 3.0.21, 3.4.6, 3.5.7, 3.6.3, 4.0.1
  • openssl Debian 12 3.0.20-1~deb12u2
  • openssl Debian 13 3.5.6-1~deb13u2
  • openssl Debian 14 3.6.3-1

debian advisories DEBIAN-CVE-2026-7383

  • openssl Ubuntu 22.04 LTS 3.0.2-0ubuntu1.25
  • openssl Ubuntu 24.04 LTS 3.0.13-0ubuntu3.11
  • openssl Ubuntu 25.10 3.5.3-1ubuntu3.4
  • openssl Ubuntu 26.04 LTS 3.5.5-1ubuntu3.2
  • openssl Ubuntu Pro 14.04 LTS 1.0.1f-1ubuntu2.27+esm14
  • openssl Ubuntu Pro 16.04 LTS 1.0.2g-1ubuntu4.20+esm16
  • openssl Ubuntu Pro 18.04 LTS 1.1.1-1ubuntu2.1~18.04.23+esm9
  • openssl Ubuntu Pro FIPS-updates 18.04 LTS 1.1.1-1ubuntu2.fips.2.1~18.04.23.9

ubuntu advisories UBUNTU-CVE-2026-7383

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

  • bootupd hummingbird 1 0.3.2-1.hum1
  • rust-bootupd hummingbird 1 0.3.2-1.hum1
  • ruby3.4 hummingbird 1 3.4.10-31.7.hum1
  • ruby3.4-libs hummingbird 1 3.4.10-31.7.hum1
  • ruby3.4-bundled-gems hummingbird 1 3.4.10-31.7.hum1
  • ruby3.4-default-gems hummingbird 1 3.4.10-31.7.hum1
  • ruby4.0 hummingbird 1 4.0.6-37.3.hum1
  • ruby4.0-libs hummingbird 1 4.0.6-37.3.hum1

red hat advisories RHSA-2026:67551RHSA-2026:62790RHSA-2026:62563RHSA-2026:62562RHSA-2026:55543RHSA-2026:42825

  • openssl-3 SLE Module for Basesystem 15 SP7 3.2.3-150700.5.36.1
  • openssl-1_1 SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE Micro 5.4 +3 more 1.1.1l-150400.7.96.2
  • openssl-3 SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE Micro 5.4 +3 more 3.0.8-150400.4.87.1
  • openssl-3 SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 3.5.0-160000.8.1
  • openssl-1_1 SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +2 more 1.1.1l-150500.17.57.2
  • openssl-1_0_0 SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +6 more 1.0.2p-150000.3.108.1
  • openssl-3 SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 3.0.8-150500.5.66.1
  • openssl-1_1 SLE Module for Legacy 15 SP7, SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 1.1.1w-150700.11.22.1

suse advisories SUSE-SU-2026:2648-1SUSE-SU-2026:2614-1SUSE-SU-2026:2598-1SUSE-SU-2026:22251-1SUSE-SU-2026:22315-1SUSE-SU-2026:2405-1

  • openssl-3 openSUSE Leap 16.0 3.5.0-160000.8.1
  • openssl-3 openSUSE Tumbleweed 3.5.3-6.1

opensuse advisories openSUSE-SU-2026:21005-1openSUSE-SU-2026:11023-1

  • openssl AlmaLinux 10 1:3.5.5-4.el10_2.alma.1
  • openssl-libs AlmaLinux 10 1:3.5.5-4.el10_2.alma.1
  • openssl-perl AlmaLinux 10 1:3.5.5-4.el10_2.alma.1
  • openssl AlmaLinux 9 1:3.5.5-4.el9_8
  • openssl-libs AlmaLinux 9 1:3.5.5-4.el9_8
  • openssl-perl AlmaLinux 9 1:3.5.5-4.el9_8

almalinux advisories ALSA-2026:25237ALSA-2026:25239

  • openssl Rocky Linux 10 1:3.5.5-4.el10_2
  • openssl Rocky Linux 9 1:3.5.5-4.el9_8

rocky linux advisories RLSA-2026:25237RLSA-2026:25239

  • openssl Alpine 3.24, Alpine 3.23, Alpine 3.22 3.5.7-r0

alpine advisories ALPINE-CVE-2026-7383

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

  • edk2 Azure Linux 3.0 20240524git3e722403cd16-18
  • openssl Azure Linux 3.0 3.3.7-3

azure linux advisories AZL-89858AZL-89928

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-2026-7383 updated cvss 5.5

openssl: OpenSSL: Heap buffer overflow due to signed integer overflow in Unicode output sizing

  • Red Hat Enterprise Linux 6 openssl, openssl-perl Red Hat Enterprise Linux 7 ovmf, OVMF, AAVMF Red Hat Enterprise Linux 8 edk2, shim, openssl, shim-x64, edk2-ovmf, shim-aa64, +9 more Red Hat Enterprise Linux 9 edk2, shim, shim-x64, edk2-ovmf, shim-aa64, edk2-tools, +4 more Red Hat Enterprise Linux 10 edk2, shim, shim-unsigned-x64, shim-unsigned-aarch64 Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.17 cert-manager/cert-manager-operator-rhel9 1791788287, cert-manager/jetstack-cert-manager-rhel9 1791371069, cert-manager/cert-manager-operator-bundle 1791970484, cert-manager/jetstack-cert-manager-acmesolver-rhel9 1791371080
    fixed: vendor fix RHSA-2026:82888
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.18 cert-manager/cert-manager-operator-rhel9 1789029076, cert-manager/jetstack-cert-manager-rhel9 1791459711, cert-manager/cert-manager-istio-csr-rhel9 1791459759, cert-manager/cert-manager-operator-bundle 1791966259, cert-manager/jetstack-cert-manager-acmesolver-rhel9 1791459707
    fixed: vendor fix RHSA-2026:82354
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.20 cert-manager/cert-manager-trust-manager-rhel9 1790598593
    fixed: vendor fix RHSA-2026:72502
  • Red Hat Discovery 2 discovery/discovery-ui-rhel9 1782166952, discovery/discovery-server-rhel9 1782159791
    fixed: vendor fix RHSA-2026:29197
  • Red Hat Enterprise Linux AppStream (v. 9) openssl-perl 3.5.5-4.el9_8
    fixed: vendor fix RHSA-2026:25239
  • Red Hat Enterprise Linux AppStream (v. 10) openssl-perl 3.5.5-4.el10_2
    fixed: vendor fix RHSA-2026:25237
  • Red Hat Enterprise Linux BaseOS (v. 9) openssl 3.5.5-4.el9_8, openssl-libs 3.5.5-4.el9_8
    fixed: vendor fix RHSA-2026:25239
show 5 more
  • Red Hat Enterprise Linux BaseOS (v. 10) openssl 3.5.5-4.el10_2, openssl-libs 3.5.5-4.el10_2
    fixed: vendor fix RHSA-2026:25237
  • Red Hat Hardened Images bootupd 0.3.2-1.hum1, chunkah 0.6.0-3.hum1, openssl 3.5.8-0.1.hum1, openssl3 3.5.8-0.1.hum1, ruby4.0 4.0.6-37.3.hum1, ruby3.3 3.3.10-23.6.hum1, +20 more
    fixed: vendor fix RHSA-2026:67551
  • Red Hat Insights proxy 1.5 insights-proxy/insights-proxy-container-rhel9 1782890503
    fixed: vendor fix RHSA-2026:34102
  • Red Hat Update Infrastructure 5 rhui5/cds-rhel9 1781525684, rhui5/rhua-rhel9 1781525739, rhui5/haproxy-rhel9 1781525671, rhui5/rhua-tp-rhel9 1787241260, rhui5/installer-rhel9 1781525693, rhui5/installer-tp-rhel9 1787135742, +1 more
    fixed: vendor fix RHSA-2026:58981
  • Red Hat Hardened Images rust, unbound, netavark, openshell, rust-podman-sequoia, rubygem3.3-rbs 3.4.0-23.6.hum1, +50 more Red Hat JBoss Core Services jbcs-httpd24-openssl, jbcs-httpd24-openssl-libs, jbcs-httpd24-openssl-perl, jbcs-openssl-win6-x86_64.zip 3.5.5-SP4 Red Hat JBoss Web Server 6 jws-optional-native-components-win6-x86_64.zip 6.2.4.ER1 Red Hat JBoss Web Server 7 jws-optional-native-components-win6-x86_64.zip 6.2.4.ER1 Red Hat Update Infrastructure 5 rhui5/cds-tp-rhel9 1787241206, rhui5/cds-kubernetes-rhel9 1781525677
    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 SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
5 mo ago

Exploit prediction

0.80% chance of exploitation in the next 30 days, higher than 56% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
OSV 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
julia AppBundler
>=1.0.0, <1.0.1
1.0.1
julia OpenSSL_jll
<3.5.7+0
3.5.7+0
julia Openresty_jll
all versions
 no fix listed

Affected products

  • OpenSSL OpenSSL

Classification

Weakness
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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.