Name Constraints bypass via trailing dot in rfc822Name and URI
Legion of the Bouncy Castle Inc. · BC-JAVA
9.3CriticalCVSS 4.0
Recommended action
Within 72 hours
Critical technical impact with a remotely reachable, unauthenticated path; no CISA KEV confirmation is currently recorded.
Patch available
Distribution package intelligence
Ubuntu vendor package status
Canonical’s release and source-package findings are shown separately from local repository availability.
1 package state
Repository candidate not checked
A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.
Ubuntu release
Source package
Vendor state
Fixed version
Evidence
Ubuntu 24.04 LTSnoble · esm-apps
bouncycastle
Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.
Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.
1 current
CVE-2026-8763 · CSAF 2.0 · revision 3 · finalRed Hat Product Securityorg.bouncycastle/bcprov-jdk15on: org.bouncycastle/bcpkix-jdk15on: Bouncy Castle for Java: Name Constraints bypass via trailing dot in rfc822Name and URI
33 known affected
The vendor explicitly identifies these products as affected by this CVE.
bcprov-jdk15on as a component of Red Hat AMQ Clients
ceph-base as a component of Red Hat Ceph Storage 9
ceph-common as a component of Red Hat Ceph Storage 9
ceph-fuse as a component of Red Hat Ceph Storage 9
ceph-immutable-object-cache as a component of Red Hat Ceph Storage 9
ceph-mib as a component of Red Hat Ceph Storage 9
ceph-resource-agents as a component of Red Hat Ceph Storage 9
ceph-selinux as a component of Red Hat Ceph Storage 9
ceph.src as a component of Red Hat Ceph Storage 9
cephadm as a component of Red Hat Ceph Storage 9
cephfs-top as a component of Red Hat Ceph Storage 9
libcephfs-devel as a component of Red Hat Ceph Storage 9
Summary
A flaw was found in Bouncy Castle for Java, a cryptographic library. An attacker can exploit this vulnerability by manipulating rfc822Name and URI fields within X.509 certificates using a trailing dot. This bypasses Name Constraints, potentially leading to spoofing or unauthorized access. Such an exploit impacts the integrity and confidentiality of communications.
Remediation
Affected
Optional official sources
National CERT insights ?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.
Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.
Official European source
ENISA European Vulnerability Database
Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.
1 current
ENISA EUVD identifier
EUVD-2026-52020
No EUVD known-exploited evidence
ENISA has published the identifier mapping but no EUVD description has been stored yet.
EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 72 hours
Critical technical impact with a remotely reachable, unauthenticated path; no CISA KEV confirmation is currently recorded.
Patch available
01
What, why and how
In Bouncy Castle for Java before 1.85, Name Constraints bypass via trailing dot in rfc822Name and URI. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bc-fips 1.0.2.7 (1.0.X series), 2.0.2 (2.0.X series) and 2.1.3 (2.1.X series).
What
In Bouncy Castle for Java before 1.85, Name Constraints bypass via trailing dot in rfc822Name and URI. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bc-fips 1.0.2.7 (1.0.X series), 2.0.2 (2.0.X series) and 2.1.3 (2.1.X series).
Why
The product does not validate, or incorrectly validates, a certificate.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
What
In Bouncy Castle for Java before 1.85, Name Constraints bypass via trailing dot in rfc822Name and URI. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bc-fips 1.0.2.7 (1.0.X series), 2.0.2 (2.0.X series) and 2.1.3 (2.1.X series).
Why
The product does not validate, or incorrectly validates, a certificate.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No confirmed evidence
No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.None recorded
No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
Likely attack path
a network path → Improper Certificate Validation → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
Weakness ?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCHighVulnerable-system confidentiality: A successful attack can cause a major loss.VIHighVulnerable-system integrity: A successful attack can cause a major loss.VANoneVulnerable-system availability: No direct loss is represented by this metric.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-295
A
Official authority intelligence
Only matched European and national findings are included. Language selectors and unavailable sources are omitted.
ENISA EUVD · EUVD-2026-52020Official EUVD mapping
0 linked advisory records.
Official EUVD recordBSI · German · WID-SEC-W-2026-2958IBM License Metric Tool: Mehrere Schwachstellen
Ein Angreifer kann mehrere Schwachstellen in IBM License Metric Tool ausnutzen, um beliebigen Programmcode auszuführen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um Dateien zu manipulieren und um Sicherheitsvorkehrungen zu umgehen.
Official advisoryBSI · German · WID-SEC-W-2026-2622Bouncy Castle: Mehrere Schwachstellen
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Bouncy Castle ausnutzen, um Sicherheitsvorkehrungen zu umgehen, Daten zu manipulieren, sensible Informationen offenzulegen oder einen Denial-of-Service-Zustand auszulösen.
Operational remediation based on structured source evidence.
Status ?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
bcprov-jdk15on as a component of Red Hat AMQ Clients; ceph-base as a component of Red Hat Ceph Storage 9; ceph-common as a component of Red Hat Ceph Storage 9; ceph-fuse as a component of Red Hat Ceph Storage 9; ceph-immutable-object-cache as a component of Red Hat Ceph Storage 9; ceph-mib as a component of Red Hat Ceph Storage 9; ceph-resource-agents as a component of Red Hat Ceph Storage 9; ceph-selinux as a component of Red Hat Ceph Storage 9; ceph.src as a component of Red Hat Ceph Storage 9; cephadm as a component of Red Hat Ceph Storage 9; cephfs-top as a component of Red Hat Ceph Storage 9; libcephfs-devel as a component of Red Hat Ceph Storage 9; libcephfs-proxy2 as a component of Red Hat Ceph Storage 9; libcephfs2 as a component of Red Hat Ceph Storage 9; librados-devel as a component of Red Hat Ceph Storage 9; librados2 as a component of Red Hat Ceph Storage 9; libradospp-devel as a component of Red Hat Ceph Storage 9; libradosstriper1 as a component of Red Hat Ceph Storage 9; librbd-devel as a component of Red Hat Ceph Storage 9; librbd1 as a component of Red Hat Ceph Storage 9; librgw-devel as a component of Red Hat Ceph Storage 9; librgw2 as a component of Red Hat Ceph Storage 9; python3-ceph-argparse as a component of Red Hat Ceph Storage 9; python3-ceph-common as a component of Red Hat Ceph Storage 9; python3-cephfs as a component of Red Hat Ceph Storage 9; python3-rados as a component of Red Hat Ceph Storage 9; python3-rbd as a component of Red Hat Ceph Storage 9; python3-rgw as a component of Red Hat Ceph Storage 9; rbd-nbd as a component of Red Hat Ceph Storage 9; bcpkix-jdk15on as a component of Red Hat JBoss Enterprise Application Platform 7; and 3 more
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04
Evidence and provenance
Published 3 Aug 2026 · Last source change 3 Aug 2026, 13:29 UTC · CWE-295 · Improper Certificate Validation
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source ?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-52020
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD enriched
Core structured fields are present and their contributing authorities are shown above.
Affected versionsThe structured affected or fixed version information changed.
Before
< 1.85; 2.73.0 < 2.73.12; 1.0.0 < 1.0.2.7; 2.0.0 < 2.0.2; 2.1.0 < 2.1.3 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
After
< 1.85; 2.73.0 < 2.73.12; 1.0.0 < 1.0.2.7; 2.0.0 < 2.0.2; 2.1.0 < 2.1.3 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Affected versionsThe structured affected or fixed version information changed.
Before
bcprov-jdk15on as a component of Red Hat AMQ Clients; ceph-base as a component of Red Hat Ceph Storage 9; ceph-common as a component of Red Hat Ceph Storage 9; ceph-fuse as a component of Red Hat Ceph Storage 9; ceph-immutable-object-cache as a component of Red Hat Ceph Storage 9; ceph-mib as a component of Red Hat Ceph Storage 9; ceph-resource-agents as a component of Red Hat Ceph Storage 9; ceph-selinux as a component of Red Hat Ceph Storage 9; ceph.src as a component of Red Hat Ceph Storage 9; cephadm as a component of Red Hat Ceph Storage 9; cephfs-top as a component of Red Hat Ceph Storage 9; libcephfs-devel as a component of Red Hat Ceph Storage 9; libcephfs-proxy2 as a component of Red Hat Ceph Storage 9; libcephfs2 as a component of Red Hat Ceph Storage 9; librados-devel as a component of Red Hat Ceph Storage 9; librados2 as a component of Red Hat Ceph Storage 9; libradospp-devel as a component of Red Hat Ceph Storage 9; libradosstriper1 as a component of Red Hat Ceph Storage 9; librbd-devel as a component of Red Hat Ceph Storage 9; librbd1 as a component of Red Hat Ceph Storage 9; librgw-devel as a component of Red Hat Ceph Storage 9; librgw2 as a component of Red Hat Ceph Storage 9; python3-ceph-argparse as a component of Red Hat Ceph Storage 9; python3-ceph-common as a component of Red Hat Ceph Storage 9; python3-cephfs as a component of Red Hat Ceph Storage 9; python3-rados as a component of Red Hat Ceph Storage 9; python3-rbd as a component of Red Hat Ceph Storage 9; python3-rgw as a component of Red Hat Ceph Storage 9; rbd-nbd as a component of Red Hat Ceph Storage 9; resteasy-javadoc (pki-core:10.6) as a component of Red Hat Enterprise Linux 8; and 14 more
After
bcprov-jdk15on as a component of Red Hat AMQ Clients; ceph-base as a component of Red Hat Ceph Storage 9; ceph-common as a component of Red Hat Ceph Storage 9; ceph-fuse as a component of Red Hat Ceph Storage 9; ceph-immutable-object-cache as a component of Red Hat Ceph Storage 9; ceph-mib as a component of Red Hat Ceph Storage 9; ceph-resource-agents as a component of Red Hat Ceph Storage 9; ceph-selinux as a component of Red Hat Ceph Storage 9; ceph.src as a component of Red Hat Ceph Storage 9; cephadm as a component of Red Hat Ceph Storage 9; cephfs-top as a component of Red Hat Ceph Storage 9; libcephfs-devel as a component of Red Hat Ceph Storage 9; libcephfs-proxy2 as a component of Red Hat Ceph Storage 9; libcephfs2 as a component of Red Hat Ceph Storage 9; librados-devel as a component of Red Hat Ceph Storage 9; librados2 as a component of Red Hat Ceph Storage 9; libradospp-devel as a component of Red Hat Ceph Storage 9; libradosstriper1 as a component of Red Hat Ceph Storage 9; librbd-devel as a component of Red Hat Ceph Storage 9; librbd1 as a component of Red Hat Ceph Storage 9; librgw-devel as a component of Red Hat Ceph Storage 9; librgw2 as a component of Red Hat Ceph Storage 9; python3-ceph-argparse as a component of Red Hat Ceph Storage 9; python3-ceph-common as a component of Red Hat Ceph Storage 9; python3-cephfs as a component of Red Hat Ceph Storage 9; python3-rados as a component of Red Hat Ceph Storage 9; python3-rbd as a component of Red Hat Ceph Storage 9; python3-rgw as a component of Red Hat Ceph Storage 9; rbd-nbd as a component of Red Hat Ceph Storage 9; bcpkix-jdk15on as a component of Red Hat JBoss Enterprise Application Platform 7; and 3 more
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
CVE-2026-8763: Name Constraints bypass via trailing dot in rfc822Name and URI | BlackTree
