Red Hat Directory Server 11.5 E4S for RHEL 8: Integer Overflow or Wraparound
CVE-2026-11774 is a high-severity integer overflow or wraparound vulnerability in Red Hat Directory Server 11.5 E4S for RHEL 8 from Red Hat, with a CVSS 3.1 base score of 7.6 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.68% chance of exploitation within 30 days, higher than 53% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Red Hat Directory Server 11.5 E4S for RHEL 8 you run against the affected versions below, and install the vendor's latest release.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- LowSome restricted data can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H. Scored by CNA (redhat.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.6 | High | CNA (redhat.com) |
| CVSS 3.1 | 7.6 | High | CNA |
Official description
An integer overflow flaw was found in the SASL I/O layer of 389 Directory Server (389-ds-base). In sasl_io_start_packet(), adding sizeof(uint32_t) to a crafted SASL packet length prefix of 0xFFFFFFFC causes unsigned wraparound to zero, bypassing the nsslapd-maxsasliosize limit and leading to a heap buffer overflow of up to approximately 2 megabytes of attacker-controlled data. After a successful SASL bind with integrity protection (SSF > 0), a remote attacker can cause a Denial of Service (DoS) or achieve Remote Code Execution (RCE). In FreeIPA and Red Hat Identity Management deployments, any domain user with a valid Kerberos ticket, enrolled host, or service account can trigger this vulnerability over the network. This flaw is independent of CVE-2025-14905, which patched schema.c only and did not modify sasl_io.c.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Integer Overflow or Wraparound
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
How developers prevent this class of flaw
- Ensure that all protocols are strictly defined, such that all out-of-bounds behavior can be identified simply, and require strict conformance to the protocol.
- Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. If possible, choose a language or compiler that performs automatic bounds checking.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Use libraries or frameworks that make it easier to handle numbers without unexpected consequences. Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++).
More Integer Overflow or Wraparound vulnerabilities (CWE-190)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
- access.redhat.com/errata/RHSA-2026:36195
- access.redhat.com/errata/RHSA-2026:36196
- access.redhat.com/errata/RHSA-2026:36197
- access.redhat.com/errata/RHSA-2026:36198
- access.redhat.com/errata/RHSA-2026:36200
- access.redhat.com/errata/RHSA-2026:36201
- access.redhat.com/errata/RHSA-2026:36202
- access.redhat.com/errata/RHSA-2026:36204
- access.redhat.com/errata/RHSA-2026:36205
- access.redhat.com/errata/RHSA-2026:36206
- access.redhat.com/errata/RHSA-2026:36208
- access.redhat.com/errata/RHSA-2026:36209
- access.redhat.com/errata/RHSA-2026:36585
- access.redhat.com/errata/RHSA-2026:36641
- access.redhat.com/errata/RHSA-2026:36660
Other vulnerabilities in Red Hat Directory Server 11.5 E4S for RHEL 8
- 8.4 High severity
- 9.8 Critical severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
Recent Integer Overflow or Wraparound vulnerabilities
- 7.5 High severity
- 9.8 Critical severity
- 7.5 High severity
- 8.8 High severity
- 8.3 High severity
- 8.3 High severity
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