VulnerabilityPublished 18 Oct 2026

CVE-2026-98802: Linux kernel · seg6: ensure packet data is writable before modifying SRH and IPv6 DA

Source GCVE Database

Authoritative record:CVE-2026-98802· Medium

Not known to be exploited : upgrade to e9141fdb7a2ead48cfcd60c681aba91d3014255b or 8ae3f4067ba4ae3a15581392f6dac422e3d3def0 when convenient.

Data as of 26 Oct 2026, 14:05 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in e9141fdb7a2ead48cfcd60c681aba91d3014255b, 8ae3f4067ba4ae3a15581392f6dac422e3d3def0

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-mq8p-h4gv-vq5x

What to do

Upgrade Linux kernel to e9141fdb7a2ead48cfcd60c681aba91d3014255b or 8ae3f4067ba4ae3a15581392f6dac422e3d3def0.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 140f04c33bbcf89440dcaf8bef04918abff5a52d, < e9141fdb7a2ead48cfcd60c681aba91d3014255b	Fixed in e9141fdb7a2ead48cfcd60c681aba91d3014255b
LinuxLinux	Affected ≥ 140f04c33bbcf89440dcaf8bef04918abff5a52d, < 8ae3f4067ba4ae3a15581392f6dac422e3d3def0	Fixed in 8ae3f4067ba4ae3a15581392f6dac422e3d3def0
LinuxLinux	Affected =4.14	Fixed in–
Red Hatredhat/kernel`pkg:rpm/redhat/kernel`Other threats	Affected =4.14	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available that adds calls to skb_ensure_writable() in advance_nextseg() and seg6_next_csid_advance_arg() to ensure packet data is writable before modification. On failure, packets are dropped to prevent data corruption. Users should apply the official Linux kernel patch that addresses this issue. No additional mitigation steps are indicated by the vendor advisory.

Description

A vulnerability in the Linux kernel's segment routing over IPv6 (seg6) implementation was resolved. The functions advance_nextseg() and seg6_next_csid_advance_arg() modified packet data without ensuring it was writable, potentially causing unintended modifications to cloned packets. This could lead to altered packet data being observed by AF_PACKET sockets receiving on ingress devices. The fix involves calling skb_ensure_writable() before modifying packet data to prevent shared data corruption. If skb_ensure_writable() fails, the packet is dropped.

References

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