In the Linux kernel, the following vulnerability has been resolved: tcp: challenge ACK for non-exact RST in SYN-RECEIVED The SYN-RECEIVED request-socket path in tcp_check_req() accepts an in-window RST without requiring SEG.SEQ to exactly match RCV.NXT. A non-exact RST therefore removes the request instead of eliciting a challenge ACK. RFC 9293 section 3.10.7.4 applies the RFC 5961 reset check in SYN-RECEIVED: an exact RST resets the connection, while a non-exact in-window RST must trigger a challenge ACK and be dropped. Apply that check before the ACK-field validation, following the RFC sequence-number, RST, then ACK processing order. Factor the per-netns challenge ACK quota out of tcp_send_challenge_ack() so request sockets can share it. Use the request socket's send_ack() callback and its own out-of-window ACK timestamp to send and rate-limit the response.

The remote Debian 13 host has packages installed that are affected by multiple vulnerabilities as referenced in the dsa-6466 advisory.

    - -------------------------------------------------------------------------     Debian Security Advisory DSA-6466-1                   security@debian.org     https://www.debian.org/security/                     Salvatore Bonaccorso     August 25, 2026                       https://www.debian.org/security/faq
    - -------------------------------------------------------------------------

    Package        : linux     CVE ID         : CVE-2025-38525 CVE-2025-40054 CVE-2026-43197 CVE-2026-53092                      CVE-2026-64017 CVE-2026-64586 CVE-2026-68082 CVE-2026-68118                      CVE-2026-68132 CVE-2026-68138 CVE-2026-68159 CVE-2026-68166                      CVE-2026-68169 CVE-2026-68198 CVE-2026-68253 CVE-2026-68254                      CVE-2026-68264 CVE-2026-68266 CVE-2026-68267 CVE-2026-68273                      CVE-2026-68276 CVE-2026-68322 CVE-2026-68367 CVE-2026-68431                      CVE-2026-68451 CVE-2026-68452 CVE-2026-68480 CVE-2026-72111                      CVE-2026-74440 CVE-2026-74441 CVE-2026-74442 CVE-2026-74443                      CVE-2026-74444 CVE-2026-74445 CVE-2026-74446 CVE-2026-74447                      CVE-2026-74448 CVE-2026-74450 CVE-2026-74451 CVE-2026-74452                      CVE-2026-74453 CVE-2026-74454 CVE-2026-74455 CVE-2026-74456                      CVE-2026-74457 CVE-2026-74458 CVE-2026-74459 CVE-2026-74460                      CVE-2026-74461 CVE-2026-74463 CVE-2026-74464 CVE-2026-74465                      CVE-2026-74467 CVE-2026-74468 CVE-2026-74469 CVE-2026-74470                      CVE-2026-74471 CVE-2026-74472 CVE-2026-74473 CVE-2026-74474                      CVE-2026-74475 CVE-2026-74476 CVE-2026-74478 CVE-2026-74479                      CVE-2026-74480 CVE-2026-74481 CVE-2026-74482 CVE-2026-74483                      CVE-2026-74484 CVE-2026-74485 CVE-2026-74487 CVE-2026-74488                      CVE-2026-74490 CVE-2026-74492 CVE-2026-74493 CVE-2026-74494                      CVE-2026-74495 CVE-2026-74497 CVE-2026-74498 CVE-2026-74499                      CVE-2026-74500 CVE-2026-74501 CVE-2026-74502 CVE-2026-74503                      CVE-2026-74504 CVE-2026-74505 CVE-2026-74507 CVE-2026-74508                      CVE-2026-74509 CVE-2026-74510 CVE-2026-74512 CVE-2026-74514                      CVE-2026-74515 CVE-2026-74516 CVE-2026-74517 CVE-2026-74518                      CVE-2026-74519 CVE-2026-74522 CVE-2026-74523 CVE-2026-74524                      CVE-2026-74525 CVE-2026-74531 CVE-2026-74532 CVE-2026-74535                      CVE-2026-74536 CVE-2026-74540 CVE-2026-74541 CVE-2026-74543                      CVE-2026-74545 CVE-2026-74546 CVE-2026-74547 CVE-2026-74548                      CVE-2026-74549 CVE-2026-74550 CVE-2026-74551 CVE-2026-74552                      CVE-2026-74553 CVE-2026-74555 CVE-2026-74556 CVE-2026-74557                      CVE-2026-74563 CVE-2026-74564 CVE-2026-74565 CVE-2026-74566                      CVE-2026-74567 CVE-2026-74569 CVE-2026-74572 CVE-2026-74574                      CVE-2026-74575 CVE-2026-74576 CVE-2026-74577 CVE-2026-74579                      CVE-2026-74580 CVE-2026-74581 CVE-2026-74582 CVE-2026-74583                      CVE-2026-74585 CVE-2026-74586 CVE-2026-74587 CVE-2026-74588                      CVE-2026-74589 CVE-2026-74590 CVE-2026-74592 CVE-2026-74594                      CVE-2026-74595 CVE-2026-74597 CVE-2026-74598 CVE-2026-74599                      CVE-2026-74601 CVE-2026-74602 CVE-2026-74603 CVE-2026-74604                      CVE-2026-74606 CVE-2026-74607 CVE-2026-74608 CVE-2026-74609                      CVE-2026-74610 CVE-2026-74612 CVE-2026-74613 CVE-2026-74614                      CVE-2026-74615 CVE-2026-74616 CVE-2026-74618 CVE-2026-74619                      CVE-2026-74620 CVE-2026-74621 CVE-2026-74622 CVE-2026-74623                      CVE-2026-74624 CVE-2026-74625 CVE-2026-74628 CVE-2026-74630                      CVE-2026-74631 CVE-2026-74632 CVE-2026-74634 CVE-2026-74635                      CVE-2026-74636 CVE-2026-74637 CVE-2026-74641 CVE-2026-74644                      CVE-2026-74646 CVE-2026-74647 CVE-2026-74648 CVE-2026-74649                      CVE-2026-74650 CVE-2026-74651 CVE-2026-74654 CVE-2026-74655                      CVE-2026-74656 CVE-2026-74657 CVE-2026-74658 CVE-2026-74659                      CVE-2026-74660 CVE-2026-74661 CVE-2026-74663 CVE-2026-74664                      CVE-2026-74665 CVE-2026-74666 CVE-2026-74667 CVE-2026-74668                      CVE-2026-74669 CVE-2026-74670 CVE-2026-74671 CVE-2026-74672                      CVE-2026-74673 CVE-2026-74675 CVE-2026-74676 CVE-2026-74677                      CVE-2026-74678 CVE-2026-74679 CVE-2026-74680 CVE-2026-74682                      CVE-2026-74683 CVE-2026-74684 CVE-2026-74685 CVE-2026-74688                      CVE-2026-74689 CVE-2026-74691 CVE-2026-74692 CVE-2026-74693                      CVE-2026-74694 CVE-2026-74696 CVE-2026-74700 CVE-2026-74701                      CVE-2026-74704 CVE-2026-74705 CVE-2026-74710 CVE-2026-74712                      CVE-2026-74714 CVE-2026-74717 CVE-2026-74718 CVE-2026-74719                      CVE-2026-74720 CVE-2026-74722 CVE-2026-74724 CVE-2026-74725                      CVE-2026-74726 CVE-2026-74730 CVE-2026-74732     Debian Bug     : 1142912 1143545

    Several vulnerabilities have been discovered in the Linux kernel that     may lead to a privilege escalation, denial of service or information     leaks.

    For the stable distribution (trixie), these problems have been fixed in     version 6.12.105-1.

    We recommend that you upgrade your linux packages.

    For the detailed security status of linux please refer to its security     tracker page at:
    https://security-tracker.debian.org/tracker/linux

    Further information about Debian Security Advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://www.debian.org/security/

    Mailing list: debian-security-announce@lists.debian.org

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - tcp: challenge ACK for non-exact RST in SYN-RECEIVED The SYN-RECEIVED request-socket path in     tcp_check_req() accepts an in-window RST without requiring SEG.SEQ to exactly match RCV.NXT. A non-exact     RST therefore removes the request instead of eliciting a challenge ACK. RFC 9293 section 3.10.7.4 applies     the RFC 5961 reset check in SYN-RECEIVED: an exact RST resets the connection, while a non-exact in-window     RST must trigger a challenge ACK and be dropped. Apply that check before the ACK-field validation,     following the RFC sequence-number, RST, then ACK processing order. Factor the per-netns challenge ACK     quota out of tcp_send_challenge_ack() so request sockets can share it. Use the request socket's send_ack()     callback and its own out-of-window ACK timestamp to send and rate-limit the response. (CVE-2026-68118)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
341888	Amazon Linux 2023 : bpftool6.18, kernel6.18, kernel6.18-devel (ALAS2023-2026-2106)	Nessus	Amazon Linux Local Security Checks	Local	high
339550	Debian dsa-6466 : ata-modules-6.12.101+deb13-armmp-di - security update	Nessus	Debian Local Security Checks	Local	medium
334202	Linux Distros Unpatched Vulnerability : CVE-2026-68118	Nessus	Misc.	Local	high

Detections

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CVE-2026-68118

high

Tenable Plugins

high

medium

high