SLES 15 — npm18 — multiple vulnerabilities (7 CVEs) — patch and remediation guide

📖 ~4 min read  •  Source: SUSE advisory SUSE-SU-2024:0643-1 (see also SUSE bugzilla)

Related CVEs: CVE-2024-21892 CVE-2025-22150 CVE-2025-23085 CVE-2024-21538 CVE-2024-22020 CVE-2024-36138 CVE-2024-27980

Upstream summary: On Linux, Node.js ignores certain environment variables if those may have been set by an unprivileged user while the process is running with elevated privileges with the only exception of CAP_NET_BIND_SERVICE. Due to a bug in the implementation of this exception, Node.js incorrectly applies this exception even when certain other capabilities have been set. This allows unprivileged users to inject code that inherits the process's elevated privileges.

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

npm18 on SLES 15 runs only when something invokes it, so there is no crash loop and no failed unit to notice — the exposure is input-driven. A developer build, a CI job, a package rebuild or triage tooling that runs objdump, readelf or gdb across an untrusted binary can hit a malformed section header and corrupt memory inside the toolchain process, running code as the build user. On a shared builder or CI runner that means tampered build output rather than downtime. npm18 is a build-time developer tool that exits when the command finishes, so there is no unit to restart — only in-flight builds and long-lived helpers such as distcc or clangd still hold the old binaries.

Environment & Reproduction

Reproduction targets SLES 15. Confirm release, registration, and installed package:

cat /etc/os-release
SUSEConnect --status-text
SUSEConnect --list-extensions 2>/dev/null | head -30
rpm -q npm18
zypper info npm18 | head -20

Exercise the workload that uses npm18 while collecting:

rpm -qa --qf '%{VENDOR}\t%{BUILDHOST}\t%{BUILDTIME:date}\t%{NAME}-%{VERSION}-%{RELEASE}\n' | awk -F'\t' '$1 !~ /SUSE/'  # packages NOT built by SUSE are your own builds - these were compiled with the vulnerable npm18 and need rebuilding
readelf -p .comment /usr/local/bin/YOURAPP  # prints e.g. 'GCC: (SUSE Linux) 7.5.0' - the compiler that actually built it (binutils; empty output just means the section was stripped)
objdump -s -j .comment /usr/local/bin/YOURAPP  # the same evidence via objdump (binutils)
sudo journalctl -xe --no-pager | tail -200
sudo tail -200 /var/log/zypp/history
sudo tail -200 /var/log/audit/audit.log
# For SUSE support, bundle evidence with supportconfig:
sudo supportconfig -R /var/tmp -B npm18

Root Cause Analysis

Root cause is documented in SUSE advisory SUSE-SU-2024:0643-1. SUSE security maintainers shipped fixes in the corresponding npm18 update for SLES 15; running an outdated build leaves the host exposed to the failure modes described in the advisory. Correlate zypper history with system logs:

sudo zypper history | grep npm18
sudo zypper history --since='-7 days' | tail -40
sudo journalctl -k | grep -i apparmor | tail -100
cat /proc/sys/kernel/tainted   # non-zero = tainted kernel / out-of-tree modules

Quick Triage

Run these on SLES 15 to capture the current state of npm18:

rpm -q npm18                              # installed NVR
rpm -V npm18                              # verify shipped files
sudo zypper patch-check                    # open patches
sudo zypper lp -r SUSE-SLE-Server-15-* 2>/dev/null | head
systemctl --failed --no-pager
sudo firewall-cmd --list-all
sudo aa-status                              # AppArmor profiles
rpm -ql npm18 | grep -E '^/(usr/lib|etc)/systemd/(system|user)/[^/]+\.(service|socket|timer|path|target|mount)$'  # the units npm18 REALLY ships - NO OUTPUT means it ships no service at all, so never run systemctl on it
rpm -ql npm18 | grep -E '^/usr/sbin/rc[^/]+$'  # SUSE-only rcNAME compat symlink (it points at /usr/sbin/service, not at a unit): the NAME after 'rc' IS the service name - bind ships /usr/sbin/rcnamed, so the unit is named.service

Step-by-Step Diagnosis

1. List failed systemd units.

   systemctl --failed --no-pager

2. Tail the journal for npm18 and the system bus.

   sudo journalctl -xe -f --no-pager

3. Inspect firewall posture (firewalld is the default on SLES 15+).

   sudo firewall-cmd --list-all-zones --permanent
   sudo nft list ruleset 2>/dev/null | head -50

4. Surface AppArmor denials and switch the profile to complain mode if needed.

   sudo journalctl -k | grep -i 'apparmor="DENIED"' | tail -30
   sudo aa-status

5. Verify npm18 integrity and reinstall if anything is altered.

   sudo rpm -V npm18
   sudo zypper verify
   sudo zypper install --force npm18

6. Correlate findings with /var/log/zypp/history, zypper history, and SUSE advisory SUSE-SU-2024:0643-1 to pin the change that introduced the regression.

Solution – Primary Fix

Apply the corrective zypper transaction referenced by SUSE advisory SUSE-SU-2024:0643-1, then reload affected systemd units:

sudo zypper ref                        # refresh repos
sudo zypper -n patch                   # apply ALL open patches (recommended)
# Or target a single package:
sudo zypper -n update npm18
# Unit name may differ from pkg name; check first:
rpm -q npm18                           # confirm new NVR

For kernel / glibc / systemd / openssl advisories a reboot is required (or SLE Live Patching where licensed):

sudo zypper ps -s                      # services using deleted libs
sudo systemctl reboot                  # or: sudo shutdown -r now
# SUSE Live Patching (kgraft / klp) avoids reboot for kernel CVEs:
sudo zypper install -y kernel-livepatch-$(uname -r | tr - _)
klp -v patches                         # active livepatches

Solution – Alternative Approaches

If the primary patch is not viable, choose from these:

• Roll back via Snapper (Btrfs snapshots taken automatically before zypper transactions on SLES 15):

  sudo snapper list
  sudo snapper undochange <pre>..<post>  # diff between two snapshot numbers
  sudo snapper rollback <pre>            # boot the host into the chosen snapshot

• Lock the package so zypper cannot upgrade it:

  sudo zypper al npm18                   # add lock
  zypper ll | grep npm18                 # list locks
  sudo zypper rl npm18                   # remove lock

• Install an older NVR if a regression is suspected:

  zypper se -s npm18                     # show all available versions
  sudo zypper install --oldpackage npm18-<older-NVR>

• Disable the AppArmor profile briefly to confirm policy is the cause, then re-enable:

  # reproduce, capture denials in the journal:
  sudo journalctl -k | grep apparmor | tail

• Where SLE Live Patching is licensed, apply kernel fixes without reboot:

  klp -v patches                         # active livepatches
  sudo zypper install -y kernel-livepatch-$(uname -r | tr - _)

Verification & Acceptance Criteria

All of these should pass after the fix:

rpm -q npm18                                            # expected fixed NVR
sudo zypper patch-check                                  # 0 critical patches outstanding
sudo firewall-cmd --list-services
sudo aa-status | head -5
sudo zypper ps -s                                        # any services still using deleted libs

The conditions described in the advisory must no longer be reported for npm18 across two consecutive runs.

Rollback Plan

Capture state before any change:

rpm -qa > /root/rpm-pre.txt
sudo zypper history list > /root/zypper-history-pre.txt
# Snapper takes pre/post snapshots automatically on Btrfs root.
sudo snapper create -d 'pre-patch-npm18'   # explicit named snapshot
sudo snapper list | head

To revert if the patch is bad:

# Preferred on Btrfs root — boot the prior snapshot:
sudo snapper rollback <snapshot-id>
sudo systemctl reboot
# Or downgrade just the package:
sudo zypper install --oldpackage npm18-<older-NVR>
# Custom security policy cleanup:

Prevention & Hardening

Reduce the chance of this recurring on SLES 15:

• Enable automatic patch installation:

  sudo zypper install -y zypper-automatic
  sudo systemctl enable --now zypper-automatic.timer
  # Or use YaST: yast2 online_update_configuration

• Subscribe to sle-security-updates and watch suse.com/support/update.

• Mirror through SUSE Manager or RMT (Repository Mirroring Tool) for controlled rollouts:

  sudo zypper install -y rmt-server rmt-cli
  sudo rmt-cli sync
  sudo rmt-cli products enable SLES/15/x86_64

• Lock sensitive packages so they cannot be auto-upgraded:

  sudo zypper al npm18

• Ensure Snapper is enabled on the root subvolume and pre/post hooks run for every zypper transaction:

  sudo snapper -c root get-config | head
  # Default zypper plugin: /usr/lib/zypp/plugins/commit/snapper.zypp-commit-plugin

• Monitor file integrity with AIDE:

  sudo zypper install -y aide
  sudo aide --init && sudo mv /var/lib/aide/aide.db.new /var/lib/aide/aide.db
  sudo aide --check

• Subscribe to SUSE Live Patching so kernel CVEs can be remediated without reboot:

  sudo SUSEConnect -p sle-module-live-patching/15.0/x86_64
  sudo zypper install -y kernel-livepatch-$(uname -r | tr - _)
  klp -v patches

• Keep AppArmor profiles in enforce; review /etc/apparmor.d/ after every package upgrade.

• Apply CIS SUSE Linux Enterprise Server Benchmark hardening.

Related Errors & Cross-Refs

Issues that commonly surface alongside a npm18 update: zypper lock contention, systemd unit ordering cycles, AppArmor denials, firewalld zone drift, and kernel taint flags. Useful triage:

sudo zypper ps -s
systemd-analyze critical-chain
sudo journalctl -k | grep apparmor | tail
sudo firewall-cmd --get-active-zones
cat /proc/sys/kernel/tainted

View all sles-15 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Primary reference: SUSE advisory SUSE-SU-2024:0643-1 (see also SUSE bugzilla). Manual pages useful on SLES 15:

man zypper
man zypper.conf
man systemctl
man journalctl
man firewall-cmd
man snapper
man apparmor
man aa-status
man SUSEConnect
man klp

Other resources: SUSE Linux Enterprise Server 15 documentation, suse.com/security, SUSE security blog, and per-package notes in /usr/share/doc/packages/npm18/ for components implicated in this advisory.