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VulnerabilityPublished Updated

CVE-2026-103603: Excessive Memory Allocation

Source GCVE Database

0
Authoritative record:CVE-2026-103603· High 8.7

Not known to be exploited · CVSS 8.7 High : upgrade to 2.7.0 soon.

Data as of 28 Oct 2026, 17:11 UTC

CVSS 4.0 base score
8.7High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 42% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 2.7.0
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

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 2 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade bc-csharp and BouncyCastle.Cryptography to 2.7.0.

Affected software

ProductAffectedFixed in
Legion of the Bouncy Castle Inc.bc-csharpAffected
  • <2.7.0
Fixed in
  • 2.7.0
NuGetBouncyCastle.Cryptographypkg:nuget/BouncyCastle.CryptographyOther threatsAffected
  • <2.7.0
Fixed in
  • 2.7.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

If you cannot patch yet, avoid processing untrusted HSS public keys or signatures. and apply patches once released.

Description

A vulnerability in the Legion of the Bouncy Castle Inc. bc-csharp library before version 2.7.0 allows remote unauthenticated attackers to cause a denial of service via memory exhaustion. This occurs due to improper validation of the level count in HSS public key parsing, leading to excessive memory allocation during signature verification.

References

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