# CVE-2026-120457: libaec through 1.1.7 Out-of-Bounds Read via m_se_decode() Second Extension Decoder

Status: published. Published: 2026-11-02. Updated: 2026-11-02.

libaec through 1.1.7 contains an out-of-bounds read vulnerability in m_se_decode() in src/decode.c that allows attackers to bypass a signed bounds check via an overlong fundamental sequence. Attackers can supply a crafted CCSDS 121.0/SZIP stream with 2^31 or more zero bits to crash the decoder or leak adjacent memory into decoded samples.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Deutsches Klimarechenzentrum / libaec: ≥ 0; ≤ 1.1.7 (affected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 5.8 (medium); CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 5.3 (medium); CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:H; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: exploitation poc; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-196

## Exploit evidence

- exploit: https://hackmd.io/@haindpwn/libaec-se-decode-fs-signedness-oob-read (ADP: CISA-ADP)

## References

- https://github.com/Deutsches-Klimarechenzentrum/libaec/issues/64 (CNA: VulnCheck; issue-tracking)

- https://github.com/Deutsches-Klimarechenzentrum/libaec/pull/66 (CNA: VulnCheck; issue-tracking, patch)

- https://github.com/Deutsches-Klimarechenzentrum/libaec/blob/v1.1.7/src/decode.c#L556-L586 (CNA: VulnCheck; technical-description)

- https://github.com/Deutsches-Klimarechenzentrum/libaec/releases/tag/v1.1.7 (CNA: VulnCheck; release-notes)

- https://hackmd.io/@haindpwn/libaec-se-decode-fs-signedness-oob-read (CNA: VulnCheck; technical-description)

- https://www.vulncheck.com/advisories/libaec-through-1.1.7-out-of-bounds-read-via-m-se-decode-second-extension-decoder (CNA: VulnCheck; third-party-advisory)

- https://hackmd.io/@haindpwn/libaec-se-decode-fs-signedness-oob-read (ADP: CISA-ADP; exploit)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-120457; retrieved 2026-11-02; source updated 2026-11-02

Revision: ebf35f6f1ef561854136d5822845768c5bb051ca41eacd7c6736ab2df699e8d8

Canonical: https://y2.dev/cve/CVE-2026-120457

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