Intel

CVE-2026-23111

Siemens ProductCERT Advisory SSA-019113

highPoCEPSS 0.5%

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: fix inverted genmask check in nft_map_catchall_activate() nft_map_catchall_activate() has an inverted element activity check compared to its non-catchall counterpart nft_mapelem_activate() and compared to what is logically required. nft_map_catchall_activate() is called from the abort path to re-activate catchall map elements that were deactivated during a failed transaction. It should skip elements that are already active (they don't need re-activation) and process elements that are inactive (they need to be restored). Instead, the current code does the opposite: it skips inactive elements and processes active ones. Compare the non-catchall activate callback, which is correct: nft_mapelem_activate(): if (nft_set_elem_active(ext, iter->genmask)) return 0; /* skip active, process inactive */ With the buggy catchall version: nft_map_catchall_activate(): if (!nft_set_elem_active(ext, genmask)) continue; /* skip inactive, process active */ The consequence is that when a DELSET operation is aborted, nft_setelem_data_activate() is never called for the catchall element. For NFT_GOTO verdict elements, this means nft_data_hold() is never called to restore the chain->use reference count. Each abort cycle permanently decrements chain->use. Once chain->use reaches zero, DELCHAIN succeeds and frees the chain while catchall verdict elements still reference it, resulting in a use-after-free. This is exploitable for local privilege escalation from an unprivileged user via user namespaces + nftables on distributions that enable CONFIG_USER_NS and CONFIG_NF_TABLES. Fix by removing the negation so the check matches nft_mapelem_activate(): skip active elements, process inactive ones.

Source: SIEMENS_ADVISORYSIEMENS_ADVISORYBSIBSI_CSAFSIEMENS_ADVISORYDEBIAN_DSADEBIAN_DSACVELISTV5NVDCVEORGEUVD

Metrics

Severity
high
Priority score
217.94
KEV status
—
Exploit maturity
PoC (publicly reported)
XIEM Effective CVSS
7.8
Source: nvd-v3
CVSS v3
7.8
CVSS v4
—
EPSS percentile
40.0 %
High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
EPSS score
0.5 %
Low — model estimates < 1% exploitation likelihood.
Published
2021-09-26 00:00 UTC
CWE
—

Reanalysis & status changes

Chronological NVD audit events for this CVE — reanalyses, CVSS updates, CPE diffs.

  1. CVE Modified2026-09-03 13:04 UTC· 416baaa9-dc9f-4396-8d5f-8c081fb06d67
    • Reference: https://git.kernel.org/stable/c/1444ff890b4653add12f734ffeffc173d42862dd
    • Reference: https://git.kernel.org/stable/c/42c574c1504aa089a0a142e4c13859327570473d
    • Reference: https://git.kernel.org/stable/c/8b68a45f9722f2babe9e7bad00aa74638addf081
    • Reference: https://git.kernel.org/stable/c/8c760ba4e36c750379d13569f23f5a6e185333f5
  2. CVE Modified2026-09-03 13:04 UTC· 134c704f-9b21-4f2e-91b3-4a467353bcc0
    • Reference: https://blog.exodusintel.com/2026/06/08/off-by-exploiting-a-use-after-free-in-the-linux-kernel/
    • Reference: https://blog.exodusintel.com/2026/06/08/off-by-exploiting-a-use-after-free-in-the-linux-kernel/
  3. CVE Modified2026-09-03 13:04 UTC· 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
    • Reference: https://access.redhat.com/errata/RHSA-2026:10108
    • Reference: https://access.redhat.com/errata/RHSA-2026:10996
    • Reference: https://access.redhat.com/errata/RHSA-2026:18134
    • Reference: https://access.redhat.com/errata/RHSA-2026:62639
  4. CVE Modified2026-09-03 13:04 UTC· 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
    • Reference: https://cert-portal.siemens.com/productcert/html/ssa-019113.html
    • Reference: https://cert-portal.siemens.com/productcert/html/ssa-082556.html
    • Reference: https://cert-portal.siemens.com/productcert/html/ssa-253495.html
    • Reference: https://cert-portal.siemens.com/productcert/html/ssa-019113.html

Affected operating systems

  • linux

    amazon / amazon_linux

  • linux

    ubuntu / awsbionic

  • linux

    ubuntu / awsjammy

  • linux

    ubuntu / awsnoble

  • linux

    ubuntu / awsresolute

  • linux

    ubuntu / awsxenial

  • linux

    ubuntu / aws-6.8jammy

  • linux

    ubuntu / aws-hwexenial

  • linux

    ubuntu / azurejammy

  • linux

    ubuntu / azurenoble

  • linux

    ubuntu / azureresolute

  • linux

    ubuntu / azurexenial

  • linux

    ubuntu / azure-4.15bionic

  • linux

    suse / basesystem_module15

  • linux

    debian / debian_linux11.0

  • linux

    debian / debian_linux12.0

  • linux

    debian / debian_linux13.0

  • linux

    suse / development_tools_module15

  • linux

    redhat / enterprise_linux10.0

  • linux

    redhat / enterprise_linux7.0

  • linux

    redhat / enterprise_linux8.0

  • linux

    redhat / enterprise_linux9.0

  • linux

    redhat / enterprise_linux_aus8.4

  • linux

    redhat / enterprise_linux_aus8.6

Affected products

Products and version ranges extracted from the vendor/CERT advisory. A range like „<4.14.6“ implies the update recommendation „upgrade to 4.14.6 or later“.

  • arista

    cloudvision_agni2024.4.0 – 2025.2.2

  • arista

    cloudvision_portal2024.2.0 – 2026.1.0

  • arista

    velocloud_edge4.5.0 – 6.4.1

  • arista

    velocloud_gateway

  • arista

    velocloud_orchestrator

  • canonical

    ubuntu_linux

  • Citrix Systems

    Hypervisor8.2 CU1 LTSR

  • Citrix Systems

    XenServer8.4

  • Dell

    ECS3.8.1.0-3.8.1.7

  • Dell

    NetWorkerVirtual Edition

  • Dell

    NetWorkervProxy 19.13.0.3

  • Dell

    NetWorkervProxy 19.14

  • Dell

    PowerScale OneFS13.2.3

  • Dell

    PowerScale OneFSOneFS

  • Dell

    Secure Connect GatewayAppliance 5.32.00.18

  • gnupg

    libgcrypt1.11.0 – 1.11.3

  • gnupg

    libgcrypt1.12.0 – 1.12.2

  • gnupg

    libgcrypt1.8.8 – 1.10.4

  • Intel

    ProzessorCore Ultra 5

  • Intel

    ProzessorCore Ultra 7

  • Intel

    ProzessorCore Ultra 9

  • julia

    openssh_jll

  • netapp

    active_iq_unified_manager

  • netapp

    clustered_data_ontap

References & sources

Linked CVEs

Show 406 more CVEs
IDCVE-2026-23111
Siemens ProductCERT Advisory SSA-019113 — CVE-2026-23111 | NEOSEC Intel