CVE-2026-15722: A stack buffer overflow flaw was found in 389 Directory Server (389-ds-base)

This month

HIGH 7.5REMOTEWATCHLISTDOWNGRADEMITIGATEMITIGATE

CVE-2026-15722 is a high-severity flaw (CVSS 7.5) affecting directory server, 389 directory server, enterprise linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A stack buffer overflow flaw was found in 389 Directory Server (389-ds-base). The get_ruvelement_from_berval() function in repl5_ruv.c copies digit characters from a network-supplied RUV berval into a fixed 16-byte stack buffer without bounds checking. A remote unauthenticated attacker can crash the LDAP server by sending a crafted StartNSDS50ReplicationRequest extended operation containing a replica ID field with more than 16 digit characters. T

Why this priority

High severity
Remotely exploitable, no login, no user action
On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.8% (top 43%)
CISA exploited list	No
Weakness	CWE-121
Published	2026-07-31
Last modified	2026-10-08

Publisher (CNA): Red Hat, Inc. · Vendor: redhat

Last updated 2026-10-08 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-31 10:16 UTCPublished CVE record published
2026-10-08 15:17 UTCUpdated Record last modified

redhat directory server DOWNGRADE

Affected: 11.0 · 12.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 11.0

1. Check installed version

apt-cache policy directory-server || rpm -q directory-server || directory-server --version

2. No fixed release: DOWNGRADE to a release before 11.0 (Debian / Ubuntu)

apt-cache madison directory-server sudo apt install directory-server=<VERSION_BEFORE_11.0> sudo apt-mark hold directory-server

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list directory-server sudo dnf downgrade directory-server-<VERSION_BEFORE_11.0> sudo dnf versionlock add directory-server

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

redhat 389 directory server MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

redhat enterprise linux MITIGATE

Affected: 7.0 · 8.0 · 9.0 · 10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Advisories and coverage

Official advisories

Amazon Linux 2 ALAS: ALAS2-2026-3926 (important): 389-ds-base 2026-09-28

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-15722?

directory server: downgrade or apply the listed mitigation; 389 directory server: mitigate or apply the listed mitigation; enterprise linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-15722 being exploited?

CVE-2026-15722 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-15722 affect?

CVE-2026-15722 affects directory server, 389 directory server, enterprise linux. Severity is high (CVSS 7.5). A stack buffer overflow flaw was found in 389 Directory Server (389-ds-base). The get_ruvelement_from_berval() function in repl5_ruv.c copies digit characters from a network-supplied RUV berval into a fixed 16-byte stack buffer without boun

How urgent is CVE-2026-15722?

Priority 51/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

Related CVEs

CVE-2026-11770 HIGH 7.5 DOWNGRADE MITIGATE A flaw was found in 389 Directory Server
CVE-2026-18651 MEDIUM 5.4 DOWNGRADE MITIGATE A flaw was found in 389 Directory Server

References

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