CVE-2017-17805: The Salsa20 encryption algorithm in the Linux kernel before 4.14.8 does not correctly handle zero-length input

Q: How do I fix CVE-2017-17805?

linux kernel: upgrade to 3.2.97, 3.16.52, 3.18.89, 4.1.49, 4.4.107, 4.9.71, 4.14.8; debian linux: mitigate or apply the listed mitigation; leap: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2017-17805 being exploited?

CVE-2017-17805 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2017-17805 affect?

CVE-2017-17805 affects linux kernel, debian linux, leap. Severity is high (CVSS 7.8). 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 AF_ALG-based skcipher interface (CONFIG_CRYPTO_USER_API_SKCIPHER) to cause a denial o

Q: How urgent is CVE-2017-17805?

Priority 42/100. High severity; On your watchlist

This month

HIGH 7.8WATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2017-17805 is a high-severity flaw (CVSS 7.8) affecting linux kernel, debian linux, leap. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 AF_ALG-based skcipher interface (CONFIG_CRYPTO_USER_API_SKCIPHER) 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 blkcipher_walk API. Both the generic implementation (crypto/s

Why this priority

High severity
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.4% (top 62%)
CISA exploited list	No
Weakness	CWE-20
Published	2017-12-20
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · linux · opensuse · opensuse project · suse

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2017-12-20 23:29 UTCPublished CVE record published
2026-06-17 01:11 UTCUpdated Record last modified

linux linux kernel UPGRADE

Affected: >= 2.6.25 and < 3.2.97 · >= 3.3 and < 3.16.52 · >= 3.17 and < 3.18.89 · >= 3.19 and < 4.1.49 · >= 4.2 and < 4.4.107 · >= 4.5 and < 4.9.71 · >= 4.10 and < 4.14.8

Fixed in: 3.2.97, 3.16.52, 3.18.89, 4.1.49, 4.4.107, 4.9.71, 4.14.8

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

debian debian linux MITIGATE

Affected: 8.0 · 9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

opensuse leap MITIGATE

Affected: 42.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 42.2

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

opensuse project leap MITIGATE

Affected: 42.3

Fixed in: no fixed release known

Safe to downgrade to: a release before 42.3

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

suse linux enterprise desktop MITIGATE

Affected: 12 sp2 · 12 sp3

Fixed in: no fixed release known

Safe to downgrade to: a release before 12

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

suse linux enterprise server MITIGATE

Affected: 11 extra · 11 sp4 · 12 sp2 · 12 sp3

Fixed in: no fixed release known

Safe to downgrade to: a release before 11

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2017-17805?

linux kernel: upgrade to 3.2.97, 3.16.52, 3.18.89, 4.1.49, 4.4.107, 4.9.71, 4.14.8; debian linux: mitigate or apply the listed mitigation; leap: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2017-17805 being exploited?

CVE-2017-17805 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2017-17805 affect?

CVE-2017-17805 affects linux kernel, debian linux, leap. Severity is high (CVSS 7.8). 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 AF_ALG-based skcipher interface (CONFIG_CRYPTO_USER_API_SKCIPHER) to cause a denial o

How urgent is CVE-2017-17805?

Priority 42/100. High severity; On your watchlist

Software pages

Linux kernel vulnerabilities · Debian vulnerabilities

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References

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