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Fencer Vulns
high 7.5

CVE-2026-54874 json

Excessive Memory Use Buffering DTLS Records for a Future Epoch

published 2026-08-25 2 mo ago modified 2026-09-11 58 d ago also EUVD-2026-65481

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 50%
public exploits
0
none known

Summary

Issue summary: Receiving a DTLS record for a future epoch while a handshake is in progress causes OpenSSL to buffer far more memory than the record itself requires.

Impact summary: A peer can use a small amount of network traffic to make an OpenSSL DTLS endpoint retain a disproportionately large amount of memory, which may lead to a Denial of Service.

CWE: CWE-405: Asymmetric Resource Consumption (Amplification)

Description: While a DTLS handshake is in progress, a peer may legitimately have already moved on to the next epoch (for example, having sent its ChangeCipherSpec and Finished messages) before the local endpoint has processed the same transition, typically because of reordering on the underlying UDP transport. OpenSSL buffers such early records so that they can be processed once the local endpoint catches up.

Buffering a record currently retains the entire read buffer it arrived in, which is sized to hold the largest possible DTLS record (around 16 kilobytes), rather than just the bytes that make up the record itself. Up to 100 such records may be buffered per connection. As a result, a peer that sends a stream of small forged records claiming to belong to the next epoch can cause an OpenSSL DTLS endpoint to retain around 1.7 megabytes of memory, despite sending only a small fraction of that amount of data over the network.

An attacker therefore gains a memory amplification factor of around 1200, and can multiply the effect across as many associations as it is able to open, making this a remote memory exhaustion Denial of Service risk for DTLS servers. Since the memory retained per connection remains bounded, and any limit an application already places on the number of concurrent associations also bounds the total exposure, this issue has been assessed as Low severity.

FIPS impact: no

No FIPS modules are affected by this issue as the affected code is outside the OpenSSL FIPS module boundary.

OpenSSL 4.0, 3.6, 3.5, 3.4, 3.0, 1.1.1 and 1.0.2 are vulnerable to this issue.

OpenSSL 4.0 users should upgrade to OpenSSL 4.0.2. OpenSSL 3.6 users should upgrade to OpenSSL 3.6.4. OpenSSL 3.5 users should upgrade to OpenSSL 3.5.8. OpenSSL 3.4 users should upgrade to OpenSSL 3.4.7. OpenSSL 3.0 users should upgrade to OpenSSL 3.0.22.

Premium support customers only: OpenSSL 1.1.1 users should upgrade to OpenSSL 1.1.1zi OpenSSL 1.0.2 users should upgrade to OpenSSL 1.0.2zr

This issue was reported on 18 May 2026 by Amazon Web Services. The fix has been developed by Matt Caswell.

-- cut (non-publishing metadata for internal use) -- Reported by: Amazon Web Services Fixed by: Matt Caswell

Patch / fix

  • OpenSSL OpenSSL 1.0.2zr, 1.1.1zi, 3.0.22, 3.4.7, 3.5.8, 3.6.4, 4.0.2
  • openssl Debian 12 3.0.22-1~deb12u1
  • openssl Debian 13 3.5.7-1~deb13u2
  • openssl Debian 14 3.6.4-1

debian advisories DEBIAN-CVE-2026-54874

  • edk2 Ubuntu 22.04 LTS 2022.02-3ubuntu0.22.04.7
  • edk2 Ubuntu 24.04 LTS 2024.02-2ubuntu0.10
  • edk2 Ubuntu 26.04 LTS 2025.11-3ubuntu7.3
  • openssl Ubuntu 22.04 LTS 3.0.2-0ubuntu1.29
  • openssl Ubuntu 24.04 LTS 3.0.13-0ubuntu3.15
  • openssl Ubuntu 26.04 LTS 3.5.5-1ubuntu3.4
  • edk2 Ubuntu Pro 16.04 LTS 0~20160408.ffea0a2c-2ubuntu0.2+esm4
  • edk2 Ubuntu Pro 18.04 LTS 0~20180205.c0d9813c-2ubuntu0.3+esm3

ubuntu advisories UBUNTU-CVE-2026-54874

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

  • openssl RHEL 9 1:3.5.8-1.el9_8
  • openssl-libs RHEL 9 1:3.5.8-1.el9_8
  • openssl-perl RHEL 9 1:3.5.8-1.el9_8
  • openssl RHEL 10.2 1:3.5.8-1.el10_2
  • openssl-libs RHEL 10.2 1:3.5.8-1.el10_2
  • openssl-perl RHEL 10.2 1:3.5.8-1.el10_2
  • openssl3 hummingbird 1 3.5.8-0.1.hum1
  • openssl3-libs hummingbird 1 3.5.8-0.1.hum1

red hat advisories RHSA-2026:67165RHSA-2026:67154RHSA-2026:59635RHSA-2026:59641

  • 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-150700.11.30.1
  • openssl-3 SLE Module for Basesystem 15 SP7 3.5.0-150700.5.50.1
  • openssl-1_1 SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE Micro 5.4 +3 more 1.1.1l-150400.7.104.1
  • openssl-3 SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE Micro 5.4 +3 more 3.0.8-150400.4.98.1
  • openssl-3 Linux Micro 6.0 3.1.4-17.1
  • openssl-3 SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 3.5.0-160000.10.1
  • openssl-3 Linux Micro 6.1 3.1.4-slfo.1.1_13.1
  • openssl-1_1 SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +2 more 1.1.1l-150500.17.63.1

suse advisories SUSE-SU-2026:4762-1SUSE-SU-2026:4043-1SUSE-SU-2026:4041-1SUSE-SU-2026:4039-1SUSE-SU-2026:4033-1SUSE-SU-2026:4032-1

  • openssl-3 openSUSE Leap 16.0 3.5.0-160000.10.1
  • openssl-3 openSUSE Tumbleweed 3.5.3-8.1

opensuse advisories openSUSE-SU-2026:21744-1openSUSE-SU-2026:11623-1

  • openssl AlmaLinux 10 1:3.5.8-1.el10_2.alma.1
  • openssl-libs AlmaLinux 10 1:3.5.8-1.el10_2.alma.1
  • openssl-perl AlmaLinux 10 1:3.5.8-1.el10_2.alma.1
  • openssl AlmaLinux 9 1:3.5.8-1.el9_8
  • openssl-libs AlmaLinux 9 1:3.5.8-1.el9_8
  • openssl-perl AlmaLinux 9 1:3.5.8-1.el9_8

almalinux advisories ALSA-2026:67154ALSA-2026:67165

  • openssl Rocky Linux 9 1:3.5.8-1.el9_8
  • openssl Rocky Linux 10 1:3.5.8-1.el10_2

rocky linux advisories RLSA-2026:67165RLSA-2026:67154

  • openssl Alpine 3.24, Alpine 3.23, Alpine 3.22 3.5.8-r0

alpine advisories ALPINE-CVE-2026-54874

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 Azure Linux 3.0 3.3.7-6

azure linux advisories AZL-97953

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-2026-54874 updated cvss 7.5

openssl: excessive memory use buffering DTLS records for a future epoch

  • Red Hat Developer Hub 1 rhdh/rhdh-hub-rhel9 Red Hat Enterprise Linux 6 openssl, openssl-perl Red Hat Enterprise Linux 7 ovmf, OVMF, shim, AAVMF, mokutil, openssl, +5 more Red Hat Enterprise Linux 8 edk2, shim, openssl, shim-x64, edk2-ovmf, shim-aa64, +10 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
    +7 more products
    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 OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9 Red Hat Satellite 6 puppet-agent, openvox-agent Red Hat Satellite Client puppet-agent, openvox-agent
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.20 cert-manager/cert-manager-operator-rhel9 1790272426, cert-manager/cert-manager-operator-rhel9 1790589855, cert-manager/jetstack-cert-manager-rhel9 1790223279, cert-manager/jetstack-cert-manager-rhel9 1790589912, cert-manager/cert-manager-istio-csr-rhel9 1790223719, cert-manager/cert-manager-istio-csr-rhel9 1790589914, +1 more
    fixed: vendor fix RHSA-2026:72475
  • Red Hat Enterprise Linux AppStream (v. 9) openssl-perl 3.5.8-1.el9_8
    fixed: vendor fix RHSA-2026:67165
  • Red Hat Enterprise Linux AppStream (v. 10) openssl-perl 3.5.8-1.el10_2
    fixed: vendor fix RHSA-2026:67154
  • Red Hat Enterprise Linux BaseOS (v. 9) openssl 3.5.8-1.el9_8, openssl-libs 3.5.8-1.el9_8
    fixed: vendor fix RHSA-2026:67165
  • Red Hat Enterprise Linux BaseOS (v. 10) openssl 3.5.8-1.el10_2, openssl-libs 3.5.8-1.el10_2
    fixed: vendor fix RHSA-2026:67154
  • Red Hat Hardened Images openssl 3.5.8-0.1.hum1, openssl3 3.5.8-0.1.hum1, openssl-libs 3.5.8-0.1.hum1, openssl-perl 3.5.8-0.1.hum1, openssl3-libs 3.5.8-0.1.hum1, openssl-config-fips 3.5.8-0.1.hum1, +3 more
    fixed: vendor fix RHSA-2026:59641
  • Red Hat Update Infrastructure 5 rhui5/cds-rhel9 1790241954, rhui5/rhua-rhel9 1790242004, rhui5/haproxy-rhel9 1790241900, rhui5/installer-rhel9 1789482961, rhui5/cds-kubernetes-rhel9 1789479916
    fixed: vendor fix RHSA-2026:67956
show 1 more
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.20 cert-manager/jetstack-cert-manager-acmesolver-rhel9 1790223630 Red Hat Hardened Images unbound Red Hat OpenShift AI (RHOAI) rhoai/odh-llama-stack-k8s-operator-rhel9 Red Hat Update Infrastructure 5 rhui5/cds-rhel9 1789479900, rhui5/rhua-rhel9 1789478095, rhui5/haproxy-rhel9 1789479891, rhui5/installer-rhel9 1790241922, rhui5/cds-kubernetes-rhel9 1790241897
    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
yes
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.62% chance of exploitation in the next 30 days, higher than 50% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • OpenSSL OpenSSL

Classification

Weakness
  • CWE-405 Asymmetric Resource Consumption (Amplification)
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.