ubuntu-cve-2026-8798
Vulnerability from osv_ubuntu
Published
2026-08-08 01:16
Modified
2026-08-13 00:02
Summary
Details
In Bouncy Castle for Java FIPS (BC-FJA) before bc-fips 2.1.3, the native entropy source used on Intel platforms retried the CPU entropy instructions without any bound. RDSEED and RDRAND report failure through their carry flag, and the JNI seeding routine spun re-issuing the instruction for as long as that flag stayed clear, so a persistent failure of the on-chip entropy source - whether from a hardware fault, from the underlying DRBG being exhausted by contention across many cores, or from a hypervisor that does not provide the instruction - left the calling thread looping indefinitely inside the JNI call, where it could be neither interrupted nor timed out. Any operation drawing from the native entropy source could therefore hang, denying service to the application. The retry loops are now bounded (200 attempts for RDSEED and 20 for RDRAND, twice the baselines given in Intel's Digital Random Number Generator software implementation guide), pausing between attempts and, on exhaustion, clearing any partially written buffer and throwing rather than continuing to spin. The clear is performed by an un-elidable memzero, which uses a volatile pointer and an assembly memory barrier so that a compiler cannot optimise the erase away as a dead store. Bouncy Castle for Java (bcprov) is not affected, as it has no native entropy source; the 1.0.X and 2.0.X FIPS series are not affected.
Severity
N/A (UNKNOWN)
References
{
"affected": [
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libbcmail-java",
"binary_version": "1.51-4ubuntu1+esm1"
},
{
"binary_name": "libbcpg-java",
"binary_version": "1.51-4ubuntu1+esm1"
},
{
"binary_name": "libbcpkix-java",
"binary_version": "1.51-4ubuntu1+esm1"
},
{
"binary_name": "libbcprov-java",
"binary_version": "1.51-4ubuntu1+esm1"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:16.04:LTS",
"name": "bouncycastle",
"purl": "pkg:deb/ubuntu/bouncycastle@1.51-4ubuntu1+esm1?arch=source\u0026distro=esm-apps/xenial"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.49+dfsg-3ubuntu1",
"1.51-4ubuntu1",
"1.51-4ubuntu1+esm1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libbcmail-java",
"binary_version": "1.59-1ubuntu0.1~esm1"
},
{
"binary_name": "libbcpg-java",
"binary_version": "1.59-1ubuntu0.1~esm1"
},
{
"binary_name": "libbcpkix-java",
"binary_version": "1.59-1ubuntu0.1~esm1"
},
{
"binary_name": "libbcprov-java",
"binary_version": "1.59-1ubuntu0.1~esm1"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:18.04:LTS",
"name": "bouncycastle",
"purl": "pkg:deb/ubuntu/bouncycastle@1.59-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/bionic"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.57-1",
"1.58-1",
"1.59-1",
"1.59-1ubuntu0.1~esm1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libbcmail-java",
"binary_version": "1.61-1ubuntu0.1~esm1"
},
{
"binary_name": "libbcpg-java",
"binary_version": "1.61-1ubuntu0.1~esm1"
},
{
"binary_name": "libbcpkix-java",
"binary_version": "1.61-1ubuntu0.1~esm1"
},
{
"binary_name": "libbcprov-java",
"binary_version": "1.61-1ubuntu0.1~esm1"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:20.04:LTS",
"name": "bouncycastle",
"purl": "pkg:deb/ubuntu/bouncycastle@1.61-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/focal"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.61-1",
"1.61-1ubuntu0.1~esm1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libbcmail-java",
"binary_version": "1.68-5ubuntu0.1~esm1"
},
{
"binary_name": "libbcpg-java",
"binary_version": "1.68-5ubuntu0.1~esm1"
},
{
"binary_name": "libbcpkix-java",
"binary_version": "1.68-5ubuntu0.1~esm1"
},
{
"binary_name": "libbcprov-java",
"binary_version": "1.68-5ubuntu0.1~esm1"
},
{
"binary_name": "libbctls-java",
"binary_version": "1.68-5ubuntu0.1~esm1"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:22.04:LTS",
"name": "bouncycastle",
"purl": "pkg:deb/ubuntu/bouncycastle@1.68-5ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/jammy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.68-2",
"1.68-4",
"1.68-5",
"1.68-5ubuntu0.1~esm1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libbcjmail-java",
"binary_version": "1.77-1ubuntu0.1~esm1"
},
{
"binary_name": "libbcmail-java",
"binary_version": "1.77-1ubuntu0.1~esm1"
},
{
"binary_name": "libbcpg-java",
"binary_version": "1.77-1ubuntu0.1~esm1"
},
{
"binary_name": "libbcpkix-java",
"binary_version": "1.77-1ubuntu0.1~esm1"
},
{
"binary_name": "libbcprov-java",
"binary_version": "1.77-1ubuntu0.1~esm1"
},
{
"binary_name": "libbctls-java",
"binary_version": "1.77-1ubuntu0.1~esm1"
},
{
"binary_name": "libbcutil-java",
"binary_version": "1.77-1ubuntu0.1~esm1"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:24.04:LTS",
"name": "bouncycastle",
"purl": "pkg:deb/ubuntu/bouncycastle@1.77-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/noble"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.72-2",
"1.77-1",
"1.77-1ubuntu0.1~esm1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libbcjmail-java",
"binary_version": "1.80-3"
},
{
"binary_name": "libbcmail-java",
"binary_version": "1.80-3"
},
{
"binary_name": "libbcpg-java",
"binary_version": "1.80-3"
},
{
"binary_name": "libbcpkix-java",
"binary_version": "1.80-3"
},
{
"binary_name": "libbcprov-java",
"binary_version": "1.80-3"
},
{
"binary_name": "libbctls-java",
"binary_version": "1.80-3"
},
{
"binary_name": "libbcutil-java",
"binary_version": "1.80-3"
}
]
},
"package": {
"ecosystem": "Ubuntu:26.04:LTS",
"name": "bouncycastle",
"purl": "pkg:deb/ubuntu/bouncycastle@1.80-3?arch=source\u0026distro=resolute"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.80-3"
]
}
],
"aliases": [],
"details": "In Bouncy Castle for Java FIPS (BC-FJA) before bc-fips 2.1.3, the native entropy source used on Intel platforms retried the CPU entropy instructions without any bound. RDSEED and RDRAND report failure through their carry flag, and the JNI seeding routine spun re-issuing the instruction for as long as that flag stayed clear, so a persistent failure of the on-chip entropy source - whether from a hardware fault, from the underlying DRBG being exhausted by contention across many cores, or from a hypervisor that does not provide the instruction - left the calling thread looping indefinitely inside the JNI call, where it could be neither interrupted nor timed out. Any operation drawing from the native entropy source could therefore hang, denying service to the application. The retry loops are now bounded (200 attempts for RDSEED and 20 for RDRAND, twice the baselines given in Intel\u0027s Digital Random Number Generator software implementation guide), pausing between attempts and, on exhaustion, clearing any partially written buffer and throwing rather than continuing to spin. The clear is performed by an un-elidable memzero, which uses a volatile pointer and an assembly memory barrier so that a compiler cannot optimise the erase away as a dead store. Bouncy Castle for Java (bcprov) is not affected, as it has no native entropy source; the 1.0.X and 2.0.X FIPS series are not affected.",
"id": "UBUNTU-CVE-2026-8798",
"modified": "2026-08-13T00:02:12Z",
"published": "2026-08-08T01:16:00Z",
"references": [
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-8798"
},
{
"type": "REPORT",
"url": "https://www.cve.org/CVERecord?id=CVE-2026-8798"
},
{
"type": "REPORT",
"url": "https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%908798"
}
],
"related": [],
"schema_version": "1.7.0",
"severity": [
{
"score": "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",
"type": "CVSS_V4"
},
{
"score": "medium",
"type": "Ubuntu"
}
],
"upstream": [
"CVE-2026-8798"
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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