CVE-2022-2906VulnerabilityPublished 21 Sep 2022Updated 28 May 2025

CVE-2022-2906: ISC BIND9 · In BIND 9.18.0 -> 9.18.6 and versions 9.19.0 -> 9.19.4 of the BIND 9.19 development branch, changes between OpenSSL 1.x and OpenSSL 3.0 expose a flaw in named that causes a small memory leak in key processing when using TKEY records in Diffie-Hellman mode with OpenSSL 3.0.0 and later versions.

Affects ISC BIND9Source CVE Database V5

Not known to be exploited · CVSS 7.5 High : upgrade to 9.19.5 or 9.18.7 soon.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 2.0% chance of exploitation in 30 days – higher than 81% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 9.19.5, 9.18.7

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 21 Sep 2022
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade debian/bind9 to 9.19.5 or 9.18.7.

Affected software

Product	Affected	Fixed in
Debiandebian/bind9`pkg:deb/debian/bind9`Other threats	Affected <9.18.7 <9.19.5	Fixed in 9.18.7 9.19.5

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

1. 2. If you cannot patch yet, consider disabling TKEY Diffie-Hellman key exchanges if feasible, to prevent triggering the vulnerable code path. 3. Monitor DNS server memory usage and named process stability closely to detect abnormal memory growth or crashes indicative of exploitation attempts. 4. Implement network-level protections such as rate limiting or filtering of TKEY DNS queries from untrusted sources to reduce attack surface. 5. Employ DNS firewalling or intrusion detection systems capable of identifying anomalous DNS traffic patterns associated with exploitation attempts. 6. Maintain updated inventories of DNS server software versions and OpenSSL dependencies to ensure timely patch management. 7. For critical DNS infrastructure, consider deploying redundant DNS servers with failover capabilities to minimize service disruption during attacks or maintenance. 8. Engage with ISC security advisories and community channels to receive timely updates on patches and mitigation guidance.

Description

An attacker can leverage this flaw to gradually erode available memory to the point where named crashes for lack of resources. Upon restart the attacker would have to begin again, but nevertheless there is the potential to deny service.

Impact

For European organizations, the impact of CVE-2022-2906 primarily manifests as a denial of service against DNS infrastructure. DNS is a critical service underpinning almost all network communications and internet services. A successful exploitation could cause DNS server crashes, leading to service outages, degraded network performance, or loss of domain resolution capabilities. This can disrupt internal and external communications, web services, email, and other dependent applications. Organizations with public-facing DNS servers or those providing DNS services to customers are at higher risk of reputational damage and operational disruption. Additionally, DNS outages can have cascading effects on security monitoring, incident response, and other dependent systems. Since the vulnerability requires no authentication or user interaction and can be exploited remotely over the network, it poses a significant risk to internet-facing DNS servers. European critical infrastructure sectors such as finance, telecommunications, government, and energy, which rely heavily on stable DNS services, could experience operational interruptions. However, the impact is limited to availability; there is no direct confidentiality or integrity compromise. The gradual nature of the memory leak means attacks may require sustained effort but can be automated. Organizations using OpenSSL 3.0 with vulnerable BIND versions are specifically at risk, which may be more common in environments adopting newer OpenSSL releases.

Summary

CVE-2022-2906 is a high-severity vulnerability affecting ISC BIND9 versions 9.18.0 through 9.18.6 and 9.19.0 through 9.19.4 (development branch). The flaw arises due to changes between OpenSSL 1.x and OpenSSL 3.0 that expose a memory leak in the named DNS server process when handling TKEY records in Diffie-Hellman mode with OpenSSL 3.0.0 or later. Specifically, the vulnerability is a small memory leak during key processing, which an attacker can exploit by repeatedly sending crafted TKEY requests. Over time, this leak gradually consumes available memory resources, eventually causing the named process to crash due to resource exhaustion. Although the service can be restarted, the attacker can repeatedly trigger the leak to cause a denial of service (DoS) condition. The vulnerability is classified under CWE-401 (Improper Release of Memory), indicating a failure to properly manage memory allocation and deallocation. The CVSS v3.1 base score is 7.5, reflecting a high severity with network attack vector, low attack complexity, no privileges or user interaction required, and impact limited to availability (no confidentiality or integrity impact). No known exploits are currently reported in the wild, but the vulnerability's nature makes it a plausible target for DoS attacks against DNS infrastructure running vulnerable BIND versions with OpenSSL 3.0 or later. This issue is particularly relevant for organizations relying on BIND9 as their authoritative or recursive DNS server, especially where TKEY Diffie-Hellman key exchanges are enabled or used. The absence of patches at the time of reporting necessitates prompt attention to updates or mitigations once available.

CWE-401Missing Release of Memory after Effective Lifetime (opens in a new tab)
Variant weaknessLikelihood of exploit: Medium
The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.
Implementation · Libraries or Frameworks
Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
Architecture and Design
Use an abstraction library to abstract away risky APIs. Not a complete solution.
Architecture and Design · Build and Compilation
Consider using the Boehm-Demers-Weiser garbage collector (bdwgc), which can help avoid leaks.
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 7 Jul 2025, 08:40 UTC

WeaknessesCWE-401

Technical details

References

Community reviews

Related threats