Vulnerability in Linux kernel (CVE-2026-89607)
Summary
Vulnerability in Linux kernel (CVE-2026-89607). Successful exploitation can lead to full system takeover.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
ecryptfs: reject oversized encrypted_key_size in parse_tag_3_packet
parse_tag_3_packet() set encrypted_key_size from the Tag 3 packet body
without bounding it against ECRYPTFS_MAX_KEY_BYTES (64). When
encrypted_key_size > 64, decrypt_passphrase_encrypted_session_key()
sets decrypted_key_size = encrypted_key_size and performs two
out-of-bounds writes:
- crypto_skcipher_decrypt() writes encrypted_key_size bytes into
decrypted_key[64] via scatterlist, overflowing into the parent
ecryptfs_auth_tok struct. - memcpy(crypt_stat->key, decrypted_key, decrypted_key_size) writes
into crypt_stat->key[64], corrupting root_iv, keysig_list, and
mutexes in ecryptfs_crypt_stat.
Only AES-192 (cipher code 0x08) enables this because it sets
crypt_stat->key_size = 24 independently of encrypted_key_size,
allowing crypto_skcipher_setkey() to succeed while encrypted_key_size
exceeds ECRYPTFS_MAX_KEY_BYTES.
The PKI decryption path (parse_tag_65_packet) already validates
decrypted_key_size <= ECRYPTFS_MAX_KEY_BYTES; the passphrase path
omits this check.
Bound encrypted_key_size against ECRYPTFS_MAX_KEY_BYTES (64) rather
than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES (512). The 64-byte limit also
protects the 512-byte encrypted_key[] buffer, so the former 512-byte
check is removed as redundant.
[tyhicks: Adjust the code comment to refer to macros representing the
buffer sizes rather than mentioning the buffer size values s…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-89607 has been found in Linux kernel.
Successful exploitation can lead to full system takeover. CVSS score: 7.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-89607" on the vendor's site.
CVE-2026-89607 (Linux kernel) — CVSS v3 7.8
Attack vector: local / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (unclassified) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: High (CVSS 7.8/10). Successful exploitation can lead to full system takeover.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web nvd.nist.gov
- web github.com