High severity · published May 23, 2026
CVE-2026-46300
net: skbuff: preserve shared-frag marker during coalescing
In wildKEV
7.8
CVSS
10.2%
EPSS
Yes
On KEV
Description
In the Linux kernel, the following vulnerability has been resolved: net: skbuff: preserve shared-frag marker during coalescing skb_try_coalesce() can attach paged frags from @from to @to. If @from has SKBFL_SHARED_FRAG set, the resulting @to skb can contain the same externally-owned or page-cache-backed frags, but the shared-frag marker is currently lost. That breaks the invariant relied on by later in-place writers. In particular, ESP input checks skb_has_shared_frag() before deciding whether an uncloned nonlinear skb can skip skb_cow_data(). If TCP receive coalescing has moved shared frags into an unmarked skb, ESP can see skb_has_shared_frag() as false and decrypt in place over page-cache backed frags. Propagate SKBFL_SHARED_FRAG when skb_try_coalesce() transfers paged frags. The tailroom copy path does not need the marker because it copies bytes into @to's linear data rather than transferring frag descriptors.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)10.2% · higher than 96% of CVEs
Exploited in the wildYes
CISA KEVListed Oct 28, 2026
Federal remediation dueOct 31, 2026
Ransomware campaign useNot known
Affected products
Which versions
KE
Kernel · Linux
3.9 through 5.10.257; 5.11 before 5.15.208; 5.16 before 6.1.174; 6.2 before 6.6.141; 6.7 before 6.12.91; 6.13 before 6.18.33; +5 more · source: NVD, KEV
LI
Linux · Linux
cef401de7be8c4e155c6746bfccf721a4fa5fab9 before 3599e6b3cc1ada96883d496a50a210d3afbb6987; cef401de7be8c4e155c6746bfccf721a4fa5fab9 before 2f2b16022a2e10ca7bccfb98db5ed2ec0f72641c; cef401de7be8c4e155c6746bfccf721a4fa5fab9 before 9d3e5fd19fe1063bf607219e8562fbd567b8e8d5; cef401de7be8c4e155c6746bfccf721a4fa5fab9 before 78bf6b6bb19541d19fbda6242e7cfe2c682763c0; cef401de7be8c4e155c6746bfccf721a4fa5fab9 before 760e1addc27ba1a7beb4a0a7e8b3e9ec49e7a34e; cef401de7be8c4e155c6746bfccf721a4fa5fab9 before 3bd9e113d50034db99d7ef69fd8e5242d15e414a; +3 more · source: vendor
NF
NVIDIA for RHEL 10 · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 10 · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 10.0 Extended Update Support · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 8 · Red Hat
All versions, or not specified · source: CISA
In the news
AdvisoryHigh
CISA Adds Two Known Exploited Vulnerabilities to Catalog
CISA has added two new vulnerabilities to its Known Exploited Vulnerabilities (KEV) Catalog , based on evidence of active exploitation. CVE-2026-41709 Broadcom VMWare ESX Insufficient Logging Vulnerability CVE-2026-46300 Linux Kernel Missing Initialization of a Variable Vulnerability These types of vulnerabilities are a frequent attack vector for malicious cyber actors and pose significant risks to the federal enterprise.  Binding Operational Directive (BOD) 26-04: Prioritizing Security Updates Based on Risk establishes vulnerability management requirements for Federal Civilian Executive Branch (FCEB) agencies. BOD 26-04 reinforces the importance of the KEV Catalog and requires federal agencies to prioritize rapid remediation of high-risk vulnerabilities, specifically those identified by Common Vulnerabilities and Exposures (CVEs) listed in CISA’s KEV Catalog on publicly exposed assets that grant total control of the asset post-exploitation, while deferring action for lower-risk vulnerabilities. BOD 26-04 further establishes basic expectations for when agencies must check whether threat actors compromised the system before the patch was applied.  While BOD 26-04 applies only to FCEB agencies, CISA encourages all organizations to adopt risk-based vulnerability management and prioritize remediation of KEV Catalog vulnerabilities . CISA will continue to add vulnerabilities to the catalog that meet the specified criteria .  Aware of an expl...
Oct 28, 2026·CISA Advisories
VulnerabilityHigh
[CISA KEV] CVE-2026-46300: Linux Kernel - Linux Kernel Missing Initialization of a Variable Vulnerability
Linux Kernel contains a missing initialization of a variable vulnerability that could allow for unintended modification of page-cache-backed data via failure to preserve the shared-fragment marker during socket buffer coalescing, causing ESP input processing to decrypt shared fragments in place. This vulnerability can be chained with CVE-2026-109618 and CVE-2026-109619 to implant PHP webshells and run commands as root.
Oct 28, 2026·CISA KEV
VulnerabilityHigh
Fragnesia: New Linux kernel LPE bug was spawned by Dirty Frag patch (CVE-2026-46300)
Researchers have found and disclosed yet another local privilege escalation (LPE) vulnerability in the Linux kernel: CVE-2026-46300, aka “Fragnesia”. The flaw is in the same class of vulnerabilities as the recently disclosed Dirty Frag bug(s). Like Dirty Frag, it affects the same Linux module (xfrm-ESP). In fact, according to Dirty Frag discoverer Hyunwoo Kim, Fragnesia was “accidentally activated” by the patch fixing one of the original Dirty Frag vulnerabilities (i.e., CVE-2026-43284). CVE-2026-46300 explained Fragnesia was … More → The post Fragnesia: New Linux kernel LPE bug was spawned by Dirty Frag patch (CVE-2026-46300) appeared first on Help Net Security .
May 14, 2026·Help Net Security
VulnerabilityHigh
New Fragnesia Linux Kernel LPE Grants Root Access via Page Cache Corruption
Details have emerged about a new variant of the recent Dirty Frag Linux local privilege escalation (LPE) vulnerability that allows local attackers to gain root access, making it the third such bug to be identified in the kernel within a span of two weeks. Codenamed Fragnesia, the security vulnerability is tracked as CVE-2026-46300 (CVSS score: 7.8) and is rooted in the Linux kernel's XFRM
May 14, 2026·The Hacker News