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No exploitation reportedFix available

CVE-2019-10639

No exploitation reported by the sources we read.

  • Published2019-07-05
  • Fixed in5.0.8
  • WeaknessCWE-326

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

The Linux kernel 4.x (starting from 4.1) and 5.x before 5.0.8 allows Information Exposure (partial kernel address disclosure), leading to a KASLR bypass. Specifically, it is possible to extract the KASLR kernel image offset using the IP ID values the kernel produces for connection-less protocols (e.g., UDP and ICMP). When such traffic is sent to multiple destination IP addresses, it is possible to obtain hash collisions (of indices to the counter array) and thereby obtain the hashing key (via enumeration). This key contains enough bits from a kernel address (of a static variable) so when the key is extracted (via enumeration), the offset of the kernel image is exposed. This attack can be carried out remotely, by the attacker forcing the target device to send UDP or ICMP (or certain other) traffic to attacker-controlled IP addresses. Forcing a server to send UDP traffic is trivial if the server is a DNS server. ICMP traffic is trivial if the server answers ICMP Echo requests (ping). For client targets, if the target visits the attacker's web page, then WebRTC or gQUIC can be used to force UDP traffic to attacker-controlled IP addresses. NOTE: this attack against KASLR became viable in 4.1 because IP ID generation was changed to have a dependency on an address associated with a network namespace.

Timeline

dates in UTC
  1. 2019-07-0523:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2019-10639?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2019-10639?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Linux linux kernel
BranchAffectedFixed in
5.0≥ 5.0, < 5.0.85.0.8
4.x≥ 4.1, ≤ 4.20.9no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. Update Linux linux kernel to 5.0.8

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • NVDCVSS 3.07.5read 2026-10-23
  • NVDCVSS 2.05read 2026-10-23
  • NVDweakness (CWE)CWE-326read 2026-10-23
  • FIRST EPSSEPSS score3.3 %2026-10-23

Technical details

CVSS v3 Vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Published
2019-07-05
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2019-10639?

The Linux kernel 4.x (starting from 4.1) and 5.x before 5.0.8 allows Information Exposure (partial kernel address disclosure), leading to a KASLR bypass. Specifically, it is possible to extract the KASLR kernel image offset using the IP ID values the kernel produces for connection-less protocols (e.g., UDP and ICMP). When such traffic is sent to multiple destination IP addresses, it is possible to obtain hash collisions (of indices to the counter array) and thereby obtain the hashing key (via enumeration). This key contains enough bits from a kernel address (of a static variable) so when the key is extracted (via enumeration), the offset of the kernel image is exposed. This attack can be carried out remotely, by the attacker forcing the target device to send UDP or ICMP (or certain other) traffic to attacker-controlled IP addresses. Forcing a server to send UDP traffic is trivial if the server is a DNS server. ICMP traffic is trivial if the server answers ICMP Echo requests (ping). For client targets, if the target visits the attacker's web page, then WebRTC or gQUIC can be used to force UDP traffic to attacker-controlled IP addresses. NOTE: this attack against KASLR became viable in 4.1 because IP ID generation was changed to have a dependency on an address associated with a network namespace.

Is CVE-2019-10639 actively exploited?

Active exploitation of CVE-2019-10639 has not been confirmed. Its EPSS score was 3.3% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2019-10639?

CVE-2019-10639 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

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