A flaw was discovered in OpenLDAP before 2.4.57 leading to an infinite loop in slapd with the cancel_extop Cancel operation, resulting in de
A flaw was discovered in OpenLDAP before 2.4.57 leading to an infinite loop in slapd with the cancel_extop Cancel operation, resulting in denial of service.
- Published
- Jan 26, 2021
- Updated
- Jun 16, 2026
- EPSS
- 77.2% · 100th percentile
- CWE
- CWE-835
Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.
Report tools
Action score
53
Plan
Add it to your regular patch cycle.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 23 / 30 · 77.2%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| openldap | openldap | cpe:2.3:a:openldap:openldap |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| apple | macos | cpe:2.3:o:apple:macos |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- apple macos11.1 and later · before 11.4
- debian debian linux10.0
- debian debian linux9.0
- openldap openldapbefore 2.4.57
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.13 | openldap | before 2.4.57-r0 | 2.4.57-r0 |
| Debian:10 | openldap | before 2.4.47+dfsg-3+deb10u5 | 2.4.47+dfsg-3+deb10u5 |
| Debian:12 | openldap | before 2.4.57+dfsg-1 | 2.4.57+dfsg-1 |
| Debian:9 | openldap | before 2.4.44+dfsg-5+deb9u7 | 2.4.44+dfsg-5+deb9u7 |
| openSUSE:Leap 15.2 | openldap2 | before 2.4.46-lp152.14.18.1 | 2.4.46-lp152.14.18.1 |
| SUSE:HPE Helion OpenStack 8 | openldap2 | before 2.4.41-18.83.1 | 2.4.41-18.83.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP2 | openldap2 | before 2.4.46-9.48.1 | 2.4.46-9.48.1 |
| SUSE:Linux Enterprise Module for Legacy 12 | openldap2 | before 2.4.41-39.1 | 2.4.41-39.1 |
| SUSE:Linux Enterprise Point of Sale 11 SP3 | openldap2 | before 2.4.26-0.74.26.1 | 2.4.26-0.74.26.1 |
| SUSE:Linux Enterprise Point of Sale 11 SP3 | openldap2-client | before 2.4.26-0.74.26.1 | 2.4.26-0.74.26.1 |
| SUSE:Linux Enterprise Server 11-SECURITY | openldap2-client-openssl1 | before 2.4.26-0.74.26.1 | 2.4.26-0.74.26.1 |
Same product
openldap: all recordsOther highest-scoring records for the same primary product.
- CVE-2022-29155In OpenLDAP 2.x before 2.5.12 and 2.6.x before 2.6.2, a SQL injection vulnerability exists in the experimental back-sql backend to slapd, vi58Plan
- CVE-2020-36228An integer underflow was discovered in OpenLDAP before 2.4.57 leading to a slapd crash in the Certificate List Exact Assertion processing, r55Plan
- CVE-2020-36221An integer underflow was discovered in OpenLDAP before 2.4.57 leading to slapd crashes in the Certificate Exact Assertion processing, result55Plan
- CVE-2020-36222A flaw was discovered in OpenLDAP before 2.4.57 leading to an assertion failure in slapd in the saslAuthzTo validation, resulting in denial 53Plan
- CVE-2006-5779OpenLDAP before 2.3.29 allows remote attackers to cause a denial of service (daemon crash) via LDAP BIND requests with long authcid names, w53Plan
- CVE-2021-27212In OpenLDAP through 2.4.57 and 2.5.x through 2.5.1alpha, an assertion failure in slapd can occur in the issuerAndThisUpdateCheck function vi49Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Alpine:openldap | 2.4.57-r0 · Alpine:v3.13 | Package registry (OSV) |
| Debian:openldap | 2.4.57+dfsg-1 · Debian:12 | Package registry (OSV) |
| openSUSE:openldap2 | 2.4.46-lp152.14.18.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| SUSE:openldap2 | 2.4.41-39.1 · SUSE:Linux Enterprise Module for Legacy 12 | Package registry (OSV) |
| SUSE:openldap2-client | 2.4.26-0.74.26.1 · SUSE:Linux Enterprise Point of Sale 11 SP3 | Package registry (OSV) |
| SUSE:openldap2-client-openssl1 | 2.4.26-0.74.26.1 · SUSE:Linux Enterprise Server 11-SECURITY | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-835 · Loop with Unreachable Exit Condition ('Infinite Loop')CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- seclists.org/fulldisclosure/2021/May/64
- seclists.org/fulldisclosure/2021/May/65
- seclists.org/fulldisclosure/2021/May/70
- bugs.openldap.org/show_bug.cgi?id=9428
- git.openldap.org/openldap/openldap/-/commit/9d0e8485f3113505743baabf1167e01e4558ccf5
- git.openldap.org/openldap/openldap/-/tags/OPENLDAP_REL_ENG_2_4_57
- lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E
- lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E
- lists.debian.org/debian-lts-announce/2021/02/msg00005.html
- security.netapp.com/advisory/ntap-20210226-0002/
- support.apple.com/kb/HT212529
- support.apple.com/kb/HT212530
- support.apple.com/kb/HT212531
- www.debian.org/security/2021/dsa-4845
Vendor advisories and official records. Exploit/PoC links are deliberately left out.