CVE-2017-17805: Input Validation
Last updated 4 July 2026
Other sources
The Salsa20 encryption algorithm in the Linux kernel before 4.14.8 does not correctly handle zero-length inputs, allowing a local attacker able to use the AFALG-based skcipher interface (CONFIGCRYPTOUSERAPISKCIPHER) to cause a denial of service (uninitialized-memory free and kernel crash) or have unspecified other impact by executing a crafted sequence of system calls that use the blkcipherwalk API. Both the generic implementation (crypto/salsa20generic.c) and x86 implementation (arch/x86/crypto/salsa20glue.c) of Salsa20 were vulnerable.
— Launchpad
The Salsa20 encryption algorithm in the Linux kernel before 4.14.8 does not correctly handle zero-length inputs, allowing a local attacker able to use the AFALG-based skcipher interface to cause a denial of service (uninitialized-memory free and kernel crash) or have unspecified other impact by executing a crafted sequence of system calls that use the blkcipherwalk API. Both the generic implementation (crypto/salsa20generic.c) and x86 implementation (arch/x86/crypto/salsa20glue.c) of Salsa20 are vulnerable.
An upstream patch:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ecaaab5649781c5a0effdaf298a925063020500e
— Red Hat
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 4.14.8 - Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 5.10.223-1Fixed in 5.10.262-1Fixed in 6.1.176-1Fixed in 6.1.180-1Fixed in 6.12.94-1Fixed in 6.12.101-1Fixed in 7.1.7-1Fixed in 7.1.8-1 - Upgrade
Upgrade
Linux kernel (Salsa20)to a version that resolves this vulnerability.Fixed in 4.14.8 - Configuration
Disable CONFIG_CRYPTO_USER_API_SKCIPHER so local attackers cannot access the AF_ALG-based skcipher interface that can trigger the Salsa20 zero-length input issue via blkcipher_walk.
Linux kernel crypto user API skcipher (CONFIG_CRYPTO_USER_API_SKCIPHER) CONFIG_CRYPTO_USER_API_SKCIPHER = disabled
Event History
Frequently Asked Questions
What is the severity of CVE-2017-17805?
CVE-2017-17805 is classified as a denial of service vulnerability affecting the Salsa20 encryption algorithm in the Linux kernel.
How do I fix CVE-2017-17805?
To fix CVE-2017-17805, upgrade the Linux kernel to version 4.14.8 or later.
Which versions of the Linux kernel are affected by CVE-2017-17805?
CVE-2017-17805 affects Linux kernel versions prior to 4.14.8, specifically versions from 2.6.25 up to 4.14.7.
What impact does CVE-2017-17805 have on systems?
The impact of CVE-2017-17805 can allow local attackers to cause a denial of service by exploiting the vulnerability.
Is CVE-2017-17805 specific to a certain Linux distribution?
CVE-2017-17805 affects multiple Linux distributions that run vulnerable versions of the Linux kernel, including Red Hat, Debian, and Ubuntu.