CyberSecBulletin
CVE-2026-53362Exploited in the wildNVD status: Analyzed

Linux Kernel Unspecified

Published Updated By the CyberSecBulletin desk

CVE-2026-53362 is a high-severity out-of-bounds write vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 14200d435af9a9eeb444f529fc2f689a236b7962, 65fb14cbebb0cd0eff903a22d33537ddc8b95769, 46f201f8b4c39633a1fa3dc12459f506d470993d as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on August 27, 2026, which means attacks have been observed in the wild.

Patch now

Attackers are already exploiting this vulnerability, according to CISA.

What to do

  1. Update Linux to 14200d435af9a9eeb444f529fc2f689a236b7962 or 65fb14cbebb0cd0eff903a22d33537ddc8b95769 or 46f201f8b4c39633a1fa3dc12459f506d470993d or 6374fb9edf72c67a118a2c214a0dddd04c921e0a, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.1.177 or 6.6.144 or 6.12.95 or 6.18.38, whichever matches your release line, or a later version.
  3. CISA's required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux773ba4fe9104a64a54d1c00f0fb6ffb95def2b03 up to, but not including, 14200d435af9a9eeb444f529fc2f689a236b7962; 773ba4fe9104a64a54d1c00f0fb6ffb95def2b03 up to, but not including, 65fb14cbebb0cd0eff903a22d33537ddc8b95769; 773ba4fe9104a64a54d1c00f0fb6ffb95def2b03 up to, but not including, 46f201f8b4c39633a1fa3dc12459f506d470993d; 773ba4fe9104a64a54d1c00f0fb6ffb95def2b03 up to, but not including, 6374fb9edf72c67a118a2c214a0dddd04c921e0a; 773ba4fe9104a64a54d1c00f0fb6ffb95def2b03 up to, but not including, e9eacf19281ea2498b36291b56c9606118c2d74e; 773ba4fe9104a64a54d1c00f0fb6ffb95def2b03 up to, but not including, 736b380e28d0480c7bc3e022f1950f31fe53a7c5; 6.014200d435af9a9eeb444f529fc2f689a236b7962, 65fb14cbebb0cd0eff903a22d33537ddc8b95769, 46f201f8b4c39633a1fa3dc12459f506d470993d, 6374fb9edf72c67a118a2c214a0dddd04c921e0a, e9eacf19281ea2498b36291b56c9606118c2d74e, 736b380e28d0480c7bc3e022f1950f31fe53a7c5
SiemensSIMATIC S7-1500 TM MFP - GNU/Linux subsystemall versionsNot stated
LinuxLinux Kernel6.0 up to, but not including, 6.1.177; 6.2 up to, but not including, 6.6.144; 6.7 up to, but not including, 6.12.95; 6.13 up to, but not including, 6.18.38; 6.19 up to, but not including, 7.1.36.1.177, 6.6.144, 6.12.95, 6.18.38, 7.1.3
SiemensSimatic S7-1500 Tm Mfp FirmwareNot specified in the recordNot stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: ipv6: account for fraggap on the paged allocation path In __ip6_append_data(), when the paged-allocation branch is taken (MSG_MORE / NETIF_F_SG / large fraglen), alloclen and pagedlen are computed as alloclen = fragheaderlen + transhdrlen; pagedlen = datalen - transhdrlen; datalen already includes fraggap (datalen = length + fraggap). When fraggap is non-zero, this is not the first skb and transhdrlen is zero. The fraggap bytes carried over from the previous skb are copied just past the fragment headers in the new skb's linear area. The linear area is therefore undersized by fraggap bytes while pagedlen is overstated by the same amount, and the copy writes past skb->end into the trailing skb_shared_info. An unprivileged user can trigger this via a UDPv6 socket using MSG_MORE together with MSG_SPLICE_PAGES. The bad accounting was introduced by commit 773ba4fe9104 ("ipv6: avoid partial copy for zc"). Before commit ce650a166335 ("udp6: Fix __ip6_append_data()'s handling of MSG_SPLICE_PAGES"), the negative copy value caused -EINVAL to be returned. That later commit allowed MSG_SPLICE_PAGES to proceed in this case, making the corruption triggerable. The non-paged branch sets alloclen to fraglen, which already accounts for fraggap because datalen does. Bring the paged branch in line by adding fraggap to alloclen and subtracting it from pagedlen. After this adjustment, copy no longer collapses to -fraggap on the paged path, so remove the stale comment describing that old arithmetic. Since a negative copy is no longer expected for a valid MSG_SPLICE_PAGES case, remove the MSG_SPLICE_PAGES exception from the negative copy check.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Write

The product writes data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.

More Out-of-bounds Write vulnerabilities (CWE-787)

Timeline

  1. CVE record published.
  2. Added to CISA's Known Exploited Vulnerabilities catalogue.
  3. CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
  4. Deadline for US federal agencies to remediate, set by CISA.
  5. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Write vulnerabilities

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