CVE-2026-12860

RSA PKCS#1 verification skips last two hash bytes in NULL-omitted path

MEDIUM

5.3

CVSS Score

Published: August 3, 2026 at 02:55 AM UTC

Updated: August 28, 2026 at 04:52 PM UTC

3 products affected across 2 vendorsBc JavaBouncy Castle for Java LtsBC Java

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Severity

MEDIUM5.3

Exploit prediction

EPSS 0.2%

SSVC

No known exploit

Description

In Bouncy Castle for Java before 1.85, RSA PKCS#1 verification skips last two hash bytes in NULL-omitted path. This issue also affects Bouncy Castle for Java LTS before 2.73.12.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Bc Java · Bouncycastle

95%

v < 1.85

Affected range stops below 1.85, so it looks safe — our inference, not a vendor statement

Bouncy Castle for Java Lts · Bouncycastle

95%

v ≤ 2.73.11

BC Java · Legion of Bouncy Castlemaven

60%

v < 1.852.73.0 ≤ v < 2.73.122.73.0

Affected range stops below 1.85, so it looks safe — our inference, not a vendor statement

Affected range stops below 2.73.12, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (3)

Source: cverecord

https://github.com/bcgit/bc-java/wiki/CVE-2026-12860

Patch

Source: cverecord

https://github.com/bcgit/bc-java/commit/ea5970ea9b2fb91d763b904692fd21089ca3e396

Vendor AdvisoryThird Party Advisory

Source: cverecord

https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9012860

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUM[email protected]

Attack Vector: NETWORK
Complexity: LOW
Privileges: NONE
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: NONE
Integrity: LOW
Availability: NONE

Vector?

Quick Info

StatusANALYZED

CWE

CWE-347

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