CVE-2026-21899
CryptoLib has an out-of-bounds read and crash vulnerability when decoding an empty Base64url string
CryptoLib provides a software-only solution using the CCSDS Space Data Link Security Protocol - Extended Procedures (SDLS-EP) to secure communications between a spacecraft running the core Flight System (cFS) and a ground station. Prior to version 1.4.3, in base64urlDecode, padding-stripping dereferences input[inputLen - 1] before checking that inputLen > 0 or that input != NULL. For inputLen == 0, this becomes an OOB read at input[-1], potentially crashing the process. If input == NULL and inputLen == 0, it dereferences NULL - 1. This issue has been patched in version 1.4.3.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- High
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
CryptoLib has an out-of-bounds read and crash vulnerability when decoding an empty Base64url string
CryptoLib provides a software-only solution using the CCSDS Space Data Link Security Protocol - Extended Procedures (SDLS-EP) to secure communications between a spacecraft running the core Flight System (cFS) and a ground station. Prior to version 1.4.3, in base64urlDecode, padding-stripping dereferences input[inputLen - 1] before checking that inputLen > 0 or that input != NULL. For inputLen == 0, this becomes an OOB read at input[-1], potentially crashing the process. If input == NULL and inputLen == 0, it dereferences NULL - 1. This issue has been patched in version 1.4.3.
- Record
CVE-2026-21899- CVSS 3.1
- 4.7 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L - Weakness
- CWE-125
- Updated
- 2026-11-02
EUVDEUVD-2026-1895
CryptoLib provides a software-only solution using the CCSDS Space Data Link Security Protocol - Extended Procedures (SDLS-EP) to secure communications between a spacecraft running the core Flight System (cFS) and a ground station. Prior to version 1.4.3, in base64urlDecode, padding-stripping dereferences input[inputLen - 1] before checking that inputLen > 0 or that input != NULL. For inputLen == 0, this becomes an OOB read at input[-1], potentially crashing the process. If input == NULL and inputLen == 0, it dereferences NULL - 1. This issue has been patched in version 1.4.3.
- Record
EUVD-2026-1895- CVSS 3.1
- 4.7 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L - Updated
- 2026-11-02
NVD
CryptoLib provides a software-only solution using the CCSDS Space Data Link Security Protocol - Extended Procedures (SDLS-EP) to secure communications between a spacecraft running the core Flight System (cFS) and a ground station. Prior to version 1.4.3, in base64urlDecode, padding-stripping dereferences input[inputLen - 1] before checking that inputLen > 0 or that input != NULL. For inputLen == 0, this becomes an OOB read at input[-1], potentially crashing the process. If input == NULL and inputLen == 0, it dereferences NULL - 1. This issue has been patched in version 1.4.3.
- Record
CVE-2026-21899- CVSS 3.1
- 4.7 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L - CVSS 3.1
- 4.9 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-125
- Updated
- 2026-11-02
OSV
CryptoLib has an out-of-bounds read and crash vulnerability when decoding an empty Base64url string
CryptoLib provides a software-only solution using the CCSDS Space Data Link Security Protocol - Extended Procedures (SDLS-EP) to secure communications between a spacecraft running the core Flight System (cFS) and a ground station. Prior to version 1.4.3, in base64urlDecode, padding-stripping dereferences input[inputLen - 1] before checking that inputLen > 0 or that input != NULL. For inputLen == 0, this becomes an OOB read at input[-1], potentially crashing the process. If input == NULL and inputLen == 0, it dereferences NULL - 1. This issue has been patched in version 1.4.3.
- Record
CVE-2026-21899- CVSS 3.1
- 4.7 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L - Weakness
- CWE-125
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-21899 is a medium vulnerability (CVSS 4.7) in Nasa Cryptolib, published January 10, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.34%, the 28th percentile. No source names a fixed version.