HighCVE-2025-37785

    Linux Kernel: Use-After-Free (CVE-2025-37785)

    Published Last modified Sources: Siemens ProductCERT, SUSE, Debian LTS, Debian, BSI, CVE.org, Msrc Update Guide, EUVD

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    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: ext4: fix OOB read when checking dotdot dir Mounting a corrupted filesystem with directory which contains '.' dir entry with rec_len == block size results in out-of-bounds read (later on, when the corrupted directory is removed). ext4_empty_dir() assumes every ext4 directory contains at least '.' and '..' as directory entries in the first data block. It first loads the '.' dir entry, performs sanity checks by calling ext4_check_dir_entry() and then uses its rec_len member to compute the location of '..' dir entry (in ext4_next_entry).

    Update Linux Kernel to version 5.4.293, Linux Kernel to version 5.10.236, Linux Kernel to version 5.15.180.

    Affected
    • Linux Kernel lt 2.6.19..5.4.293
    • Linux Kernel lt 5.5..5.10.236
    • Linux Kernel lt 5.11..5.15.180
    • Linux Kernel lt 5.16..6.1.134
    • Linux Kernel lt 6.2..6.6.87
    • Linux Kernel lt 6.7..6.12.23
    • Linux Kernel lt 6.13..6.13.11
    • Linux Kernel lt 6.14..6.14.2
    Fixed in
    • Linux Kernel 5.4.293
    • Linux Kernel 5.10.236
    • Linux Kernel 5.15.180
    • Linux Kernel 6.1.134
    • Linux Kernel 6.6.87
    • Linux Kernel 6.12.23
    • Linux Kernel 6.13.11
    • Linux Kernel 6.14.2
    • Linux Kernel 6.15

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    7.8

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: Vendor (CNA), CVSS v3

    7.8

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: Siemens ProductCERT, SUSE, Debian LTS, Debian, BSI, CVE.org, Msrc Update Guide, EUVD

    0.3 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 24.4

    Show all metrics
    Severity
    High
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    52.34 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    no public PoC known
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    7.8 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    7.8
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    0.3 %
    Low — model estimates < 1% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    24.4
    Elevated — this CVE ranks above at least 10% of all CVEs scored today.
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    —
    Published

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    In the Linux kernel, the following vulnerability has been resolved: ext4: fix OOB read when checking dotdot dir Mounting a corrupted filesystem with directory which contains '.' dir entry with rec_len == block size results in out-of-bounds read (later on, when the corrupted directory is removed). ext4_empty_dir() assumes every ext4 directory contains at least '.' and '..' as directory entries in the first data block. It first loads the '.' dir entry, performs sanity checks by calling ext4_check_dir_entry() and then uses its rec_len member to compute the location of '..' dir entry (in ext4_next_entry). It assumes the '..' dir entry fits into the same data block. If the rec_len of '.' is precisely one block (4KB), it slips through the sanity checks (it is considered the last directory entry in the data block) and leaves "struct ext4_dir_entry_2 *de" point exactly past the memory slot allocated to the data block. The following call to ext4_check_dir_entry() on new value of de then dereferences this pointer which results in out-of-bounds mem access. Fix this by extending __ext4_check_dir_entry() to check for '.' dir entries that reach the end of data block. Make sure to ignore the phony dir entries for checksum (by checking name_len for non-zero). Note: This is reported by KASAN as use-after-free in case another structure was recently freed from the slot past the bound, but it is really an OOB read. This issue was found by syzkaller tool. Call Trace: [ 38.594108] BUG: KASAN: slab-use-after-free in __ext4_check_dir_entry+0x67e/0x710 [ 38.594649] Read of size 2 at addr ffff88802b41a004 by task syz-executor/5375 [ 38.595158] [ 38.595288] CPU: 0 UID: 0 PID: 5375 Comm: syz-executor Not tainted 6.14.0-rc7 #1 [ 38.595298] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 [ 38.595304] Call Trace: [ 38.595308] <TASK> [ 38.595311] dump_stack_lvl+0xa7/0xd0 [ 38.595325] print_address_description.constprop.0+0x2c/0x3f0 [ 38.595339] ? __ext4_check_dir_entry+0x67e/0x710 [ 38.595349] print_report+0xaa/0x250 [ 38.595359] ? __ext4_check_dir_entry+0x67e/0x710 [ 38.595368] ? kasan_addr_to_slab+0x9/0x90 [ 38.595378] kasan_report+0xab/0xe0 [ 38.595389] ? __ext4_check_dir_entry+0x67e/0x710 [ 38.595400] __ext4_check_dir_entry+0x67e/0x710 [ 38.595410] ext4_empty_dir+0x465/0x990 [ 38.595421] ? __pfx_ext4_empty_dir+0x10/0x10 [ 38.595432] ext4_rmdir.part.0+0x29a/0xd10 [ 38.595441] ? __dquot_initialize+0x2a7/0xbf0 [ 38.595455] ? __pfx_ext4_rmdir.part.0+0x10/0x10 [ 38.595464] ? __pfx___dquot_initialize+0x10/0x10 [ 38.595478] ? down_write+0xdb/0x140 [ 38.595487] ? __pfx_down_write+0x10/0x10 [ 38.595497] ext4_rmdir+0xee/0x140 [ 38.595506] vfs_rmdir+0x209/0x670 [ 38.595517] ? lookup_one_qstr_excl+0x3b/0x190 [ 38.595529] do_rmdir+0x363/0x3c0 [ 38.595537] ? __pfx_do_rmdir+0x10/0x10 [ 38.595544] ? strncpy_from_user+0x1ff/0x2e0 [ 38.595561] __x64_sys_unlinkat+0xf0/0x130 [ 38.595570] do_syscall_64+0x5b/0x180 [ 38.595583] entry_SYSCALL_64_after_hwframe+0x76/0x7e

    Source: siemens_advisory, suse_csaf, Debian LTS Advisories, Debian Security Advisories, BSI WID Portal, BSI CSAF, cvelistv5, NVD (NIST), Microsoft Security Update Guide, CVE.org (MITRE), ENISA EUVD

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    LinuxLinux
    • —
    • 6.7 – < 6.12.23
    • 5.5 – < 5.10.236
    • 5.16 – < 6.1.134
    • 6.2 – < 6.6.87
    • 6.13 – < 6.13.11
    • 2.6.19 – < 5.4.293
    • 6.14 – < 6.14.2
    • 5.11 – < 5.15.180
    • 6.15
    • 6.12.23
    • 5.10.236
    • 6.1.134
    • 6.6.87
    • 6.13.11
    • 5.4.293
    • 6.14.2
    • 5.15.180
    DellPowerProtect Data Domain OS
    • < 8.3.1.20
    • < 8.3.1.30
    • < 8.7.0.1
    • < 7.13.1.60
    • < 7.13.1.70
    • < 8.6.0.0
    • < 8.7.0.0
    • 8.3.1.20
    • 8.3.1.30
    • 8.7.0.1
    • 7.13.1.60
    • 7.13.1.70
    • 8.6.0.0
    • 8.7.0.0

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbookworm
    Linuxdebianlinuxbullseye
    Linuxdebianlinux-6.1bullseye
    Linuxlinuxlinux_kernel—

    References & sources

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. Record modifiedLinux

      Show 26 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
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      https://git.kernel.org/stable/c/14da7dbecb430e35b5889da8dae7bef33173b351
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      https://git.kernel.org/stable/c/52a5509ab19a5d3afe301165d9b5787bba34d842
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      https://git.kernel.org/stable/c/53bc45da8d8da92ec07877f5922b130562eb4b00
      Referenceadded
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      https://git.kernel.org/stable/c/89503e5eae64637d0fa2218912b54660effe7d93
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      https://git.kernel.org/stable/c/ac28c5684c1cdab650a7e5065b19e91577d37a4b
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      https://git.kernel.org/stable/c/b47584c556444cf7acb66b26a62cbc348eb92b78
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      https://git.kernel.org/stable/c/b7531a4f99c3887439d778afaf418d1a01a5f01b
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      https://git.kernel.org/stable/c/d5e206778e96e8667d3bde695ad372c296dc9353
      Referenceadded
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      https://git.kernel.org/stable/c/e47f472a664d70a3d104a6c2a035cdff55a719b4
      Referenceremoved
      https://git.kernel.org/stable/c/14da7dbecb430e35b5889da8dae7bef33173b351
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      Referenceremoved
      https://git.kernel.org/stable/c/52a5509ab19a5d3afe301165d9b5787bba34d842
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      https://git.kernel.org/stable/c/53bc45da8d8da92ec07877f5922b130562eb4b00
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      https://git.kernel.org/stable/c/89503e5eae64637d0fa2218912b54660effe7d93
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      https://git.kernel.org/stable/c/ac28c5684c1cdab650a7e5065b19e91577d37a4b
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      Referenceremoved
      https://git.kernel.org/stable/c/b47584c556444cf7acb66b26a62cbc348eb92b78
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      Referenceremoved
      https://git.kernel.org/stable/c/b7531a4f99c3887439d778afaf418d1a01a5f01b
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      https://git.kernel.org/stable/c/d5e206778e96e8667d3bde695ad372c296dc9353
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      Referenceremoved
      https://git.kernel.org/stable/c/e47f472a664d70a3d104a6c2a035cdff55a719b4
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/52a5509ab19a5d3afe301165d9b5787bba34d842 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/53bc45da8d8da92ec07877f5922b130562eb4b00 Types: Patch
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      Reference typeremoved
      https://git.kernel.org/stable/c/89503e5eae64637d0fa2218912b54660effe7d93 Types: Patch
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      Reference typeremoved
      https://git.kernel.org/stable/c/ac28c5684c1cdab650a7e5065b19e91577d37a4b Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/b47584c556444cf7acb66b26a62cbc348eb92b78 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/b7531a4f99c3887439d778afaf418d1a01a5f01b Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/d5e206778e96e8667d3bde695ad372c296dc9353 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/e47f472a664d70a3d104a6c2a035cdff55a719b4 Types: Patch
      —

      Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    2. Record modifiedCVE Program

      Show 4 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html
      Referenceadded
      —
      https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html
      Referenceremoved
      https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html
      —
      Referenceremoved
      https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html
      —

      Source identifier: af854a3a-2127-422b-91ae-364da2661108

    3. Record modifiedSiemens ADP

      Show 4 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2025/37xxx/CVE-2025-37785.json">CVE-2025-37785</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-019113.html
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-457936.html
      Referenceremoved
      https://cert-portal.siemens.com/productcert/html/ssa-019113.html
      —

      Source identifier: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e

    4. Record modifiedLinux

      CVSS V3.1: AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      CVSSadded
      —
      AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

      Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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