Linux Kernel up to 7.3-rc4 skbuff skb_checksum_setup_ipv6 integer underflow

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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9.5$5k-$25k0.44-

Summaryinfo

A vulnerability labeled as very critical has been found in Linux Kernel up to 7.3-rc4. Affected by this issue is the function skb_checksum_setup_ipv6 of the component skbuff. The manipulation results in integer underflow. This vulnerability is reported as CVE-2026-98573. The attack can be launched remotely. No exploit exists. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as very critical has been found in Linux Kernel up to 7.3-rc4. Affected is the function skb_checksum_setup_ipv6 of the component skbuff. The manipulation with an unknown input leads to a integer underflow vulnerability. CWE is classifying the issue as CWE-191. The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: net: skbuff: fix pull-bound underflow in skb_checksum_setup_ipv6() skb_maybe_pull_tail() subtracts skb_headlen(skb) from the unsigned max argument and passes the result to __pskb_pull_tail() as a signed int. The function does not ensure that max is at least skb_headlen(skb). This can happen while parsing IPv6 extension headers when an skb already has a linear area larger than MAX_IPV6_HDR_LEN. Once the parser needs data beyond the linear area, max - skb_headlen(skb) wraps and is converted to a negative delta. __pskb_pull_tail() then passes that negative length to skb_copy_bits(), where it can become a very large copy length. Pass the requested length itself as the pull bound at the three extension-header call sites, so the delta can no longer go negative.

The advisory is available at git.kernel.org. This vulnerability is traded as CVE-2026-98573 since 09/25/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 10/18/2026).

Upgrading to version 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.55, 7.2.9 or 7.3-rc5 eliminates this vulnerability. Applying the patch 9c4e432132a97b82edf28fa172c39f743e6bfb26/718747afa5463d9cc5fd9a09f03b2a492edd9b78/a0ad0473c09d2e947aecac5c82e637ec85924b12/b2da5ed3d8c75e1b729a21b6d3beaed415e263f6/6c28c31f051dbf49c71ba7ab7bb9bc905fa1d14b/cfa643f2ca36c6f913fe1a2ceb12412ebb0fd962/d7f474226809471dc7877435e9c492cc914df0bf/3b4e0b0c008a8c1b474730248cd5b873026c74bd is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 10.0
VulDB Meta Temp Score: 9.5

VulDB Base Score: 10.0
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Integer underflow
CWE: CWE-191 / CWE-189
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.10.271/5.15.222/6.1.189/6.6.158/6.12.112/6.18.55/7.2.9/7.3-rc5
Patch: 9c4e432132a97b82edf28fa172c39f743e6bfb26/718747afa5463d9cc5fd9a09f03b2a492edd9b78/a0ad0473c09d2e947aecac5c82e637ec85924b12/b2da5ed3d8c75e1b729a21b6d3beaed415e263f6/6c28c31f051dbf49c71ba7ab7bb9bc905fa1d14b/cfa643f2ca36c6f913fe1a2ceb12412ebb0fd962/d7f474226809471dc7877435e9c492cc914df0bf/3b4e0b0c008a8c1b474730248cd5b873026c74bd

Timelineinfo

09/25/2026 CVE reserved
10/18/2026 +23 days Advisory disclosed
10/18/2026 +0 days VulDB entry created
10/18/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-98573 (🔒)
GCVE (CVE): GCVE-0-2026-98573
GCVE (VulDB): GCVE-100-422082

Entryinfo

Created: 10/18/2026 20:14
Changes: 10/18/2026 20:14 (59)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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