CVE-2026-59638

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Source
https://cve.org/CVERecord?id=CVE-2026-59638
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-59638.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-59638
Downstream
CLEANSTART (2)
DEBIAN (1)
openSUSE (2)
SUSE (3)
UBUNTU (1)
Related
openSUSE (2)
SUSE (3)
Published
2026-08-03T00:57:31Z
Modified
2026-10-24T14:39:21Z
Severity
  • 9.3 (Critical) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/U:Amber CVSS Calculator
Summary
JSSE hostname verifier CN-fallback enabled by default despite documented opt-in
Details

In Bouncy Castle for Java before 1.85, JSSE hostname verifier CN-fallback enabled by default despite documented opt-in. 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).

Database specific 
{
    "cna_assigner":  "bcorg",
    "cwe_ids":  [
        "CWE-297"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59638.json",
    "unresolved_ranges":  [
        {
            "extracted_events":  [
                {
                    "range":  [
                        {
                            "introduced":  "1.0.7"
                        },
                        {
                            "fixed":  "1.0.24"
                        },
                        {
                            "introduced":  "2.0.0"
                        },
                        {
                            "fixed":  "2.0.24"
                        },
                        {
                            "introduced":  "2.1.0"
                        },
                        {
                            "fixed":  "2.1.24"
                        }
                    ],
                    "source":  "AFFECTED_FIELD",
                    "strategy":  "StandardRange"
                }
            ]
        }
    ]
}
References

Affected packages

Git / github.com/bcgit/bc-java

Affected ranges

Type
GIT
Repo
https://github.com/bcgit/bc-java
Events
Introduced
0f1260dc7e3c42be130c45fdad5b4363170ddf32
Fixed
57fbd3c501f7a369f64eda311d6a709fc0bcae84
Fixed
799bd15320a6310a447863638aa3df64acef829b
Fixed
5ac55351cd1a8a7184d41c96a7ee87df0770240a
Database specific
Show details 
{
    "extracted_events":  [
        {
            "range":  [
                {
                    "introduced":  "1.61"
                },
                {
                    "fixed":  "1.85"
                }
            ],
            "source":  "AFFECTED_FIELD",
            "strategy":  "StandardRange"
        },
        {
            "range":  [
                {
                    "fixed":  "799bd15320a6310a447863638aa3df64acef829b"
                }
            ],
            "source":  "REFERENCES_COMMIT"
        },
        {
            "range":  [
                {
                    "fixed":  "5ac55351cd1a8a7184d41c96a7ee87df0770240a"
                }
            ],
            "source":  "REFERENCES_COMMIT"
        }
    ]
}
Type
GIT
Repo
https://github.com/bcgit/bc-lts-java
Events
Introduced
468b5082f3f0971e80bf9edb7029c17b39b9ba0c
Fixed
f101b232c5d3e07ecdd504210a57e43831d6cd65
Database specific
Show details 
{
    "extracted_events":  [
        {
            "range":  [
                {
                    "introduced":  "2.73.0"
                },
                {
                    "fixed":  "2.73.12"
                }
            ],
            "source":  "AFFECTED_FIELD",
            "strategy":  "StandardRange"
        },
        {
            "cpe":  "cpe:2.3:a:bouncycastle:bouncy_castle_for_java_lts:*:*:*:*:*:*:*:*",
            "range":  [
                {
                    "introduced":  "0"
                },
                {
                    "last_affected":  "2.73.11"
                }
            ],
            "source":  "CPE_RANGE"
        }
    ]
}

Affected versions

Other
r2rv73dot0
r2rv73dot1
r2rv73dot10
r2rv73dot11
r2rv73dot3
r2rv73dot4
r2rv73dot6
r2rv73dot8
r2rv73dot9

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-59638.json"
vanir_signatures 
[
    {
        "deprecated":  false,
        "digest":  {
            "function_hash":  "101243177317955593101504553558978546778",
            "length":  1789
        },
        "id":  "CVE-2026-59638-0f976f65",
        "signature_type":  "Function",
        "signature_version":  "v1",
        "source":  "https://github.com/bcgit/bc-java/commit/799bd15320a6310a447863638aa3df64acef829b",
        "target":  {
            "file":  "tls/src/main/java/org/bouncycastle/jsse/provider/HostnameUtil.java",
            "function":  "checkHostname"
        }
    },
    {
        "deprecated":  false,
        "digest":  {
            "line_hashes":  [
                "96001466807666051162215343109763009601",
                "189586970452718852126709800966206076350",
                "334434604823266146796290254048024465296",
                "230984720223366777099573014615205534404"
            ],
            "threshold":  0.9
        },
        "id":  "CVE-2026-59638-c6e56e73",
        "signature_type":  "Line",
        "signature_version":  "v1",
        "source":  "https://github.com/bcgit/bc-java/commit/799bd15320a6310a447863638aa3df64acef829b",
        "target":  {
            "file":  "tls/src/main/java/org/bouncycastle/jsse/provider/HostnameUtil.java"
        }
    }
]
vanir_signatures_modified 
"2026-10-24T14:39:21Z"