Skip to content
Fencer Vulns
high 7.5

CVE-2026-59646 json

DTLS handshake reassembler allocates buffer from unchecked 24-bit length

published 2026-08-03 3 mo ago modified 2026-08-28 2 mo ago also EUVD-2026-52028

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits
0
none known

Summary

In Bouncy Castle for Java before 1.85, DTLS handshake reassembler allocates buffer from unchecked 24-bit length. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bctls-fips 1.0.24 (1.0.X series), 2.0.24 (2.0.X series) and 2.1.24 (2.1.X series).

Patch / fix

  • Legion of the Bouncy Castle Inc. BC-JAVA 1.85
  • Legion of the Bouncy Castle Inc. BC-LTS-JAVA 2.73.12
  • Legion of the Bouncy Castle Inc. BC-FJA 1.0.24, 2.0.24, 2.1.24
  • bouncycastle Debian 14 1.86-1

debian advisories DEBIAN-CVE-2026-59646

  • bouncycastle SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +8 more 1.85-150200.3.38.1
  • bouncycastle SLES 16.0, SLES for SAP applications 16.0 1.85-160000.1.1

suse advisories SUSE-SU-2026:3559-1SUSE-SU-2026:23127-1SUSE-SU-2026:23150-1

  • bouncycastle openSUSE Leap 16.0 1.85-160000.1.1
  • bouncycastle openSUSE Tumbleweed 1.85-1.1

opensuse advisories openSUSE-SU-2026:21538-1openSUSE-SU-2026:11445-1

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-2026-59646 updated cvss 7.5

org.bouncycastle/bc-java: org.bouncycastle/bctls-fips: Bouncy Castle for Java: Denial of Service via unchecked DTLS handshake reassembler buffer allocation

  • Red Hat Fuse 7 bctls-jdk18on
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Satellite 6.16 for RHEL 8 openvox-server 8.17.0-1.el8sat Red Hat Satellite 6.16 for RHEL 9 openvox-server 8.17.0-1.el9sat
    fixed: vendor fix RHSA-2026:92858
  • Red Hat Satellite 6.17 for RHEL 9 openvox-server 8.17.0-1.el9sat
    fixed: vendor fix RHSA-2026:92859
  • Red Hat Satellite 6.18 for RHEL 9 openvox-server 8.17.0-1.el9sat
    fixed: vendor fix RHSA-2026:92860
  • Red Hat Satellite 6.19 for RHEL 9 openvox-server 8.17.0-1.el9sat
    fixed: vendor fix RHSA-2026:92861
  • Red Hat Satellite 6.16 for RHEL 8 openvox-agent 8.31.1-1.el8sat, yggdrasil-worker-forwarder 0.1.1-1.el8sat Red Hat Satellite 6.16 for RHEL 9 openvox-agent 8.31.1-1.el9sat, yggdrasil-worker-forwarder 0.1.1-1.el9sat Red Hat Satellite 6.17 for RHEL 9 openvox-agent 8.31.1-1.el9sat, yggdrasil-worker-forwarder 0.1.1-1.el9sat Red Hat Satellite 6.18 for RHEL 9 openvox-agent 8.31.1-1.el9sat, yggdrasil-worker-forwarder 0.1.1-1.el9sat Red Hat Satellite 6.19 for RHEL 9 openvox-agent 8.31.1-1.el9sat, python3.12-brotli 1.2.1-1.el9pc, python3.12-django 4.2.30-3.el9pc, python3.12-pillow 13.0.0-1.el9pc, python3.12-urllib3 2.8.0-1.el9pc, python3.12-gitpython 3.2.1-1.el9pc, +2 more
    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
3 mo ago

Exploit prediction

0.46% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/U:Amber
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Amber
NVD 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

  • Legion of the Bouncy Castle Inc. BC-JAVA
  • Legion of the Bouncy Castle Inc. BC-LTS-JAVA
  • Legion of the Bouncy Castle Inc. BC-FJA

Classification

Weakness
  • CWE-789 Memory Allocation with Excessive Size Value

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.