VulnerabilityPublished 13 Aug 2026Updated 29 Oct 2026

CVE-2026-47734: Poetry · Dulwich has unbounded memory allocation in receive-pack from crafted thin packs

Affects poetrySource GCVE Database

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Authoritative record:CVE-2026-47734· Medium 5.7

Not known to be exploited · CVSS 5.7 Medium : upgrade to 2.4.1_3 when convenient.

Data as of 30 Oct 2026, 08:17 UTC

CVSS 3.1 base score

5.7Medium

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

Patch: Available – fixed in 2.4.1_3

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: Required
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: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
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 10 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 29 Oct 2026.

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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity 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 poetry to 2.4.1_3.

Affected software

Product	Affected	Fixed in
Homebrewpoetry`pkg:brew/poetry`Other threats	Affected >=1.2.0 <2.4.1_3	Fixed in 2.4.1_3

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

AI-suggested

Upgrade Dulwich to version 1.2.5 or later, preferably 2.4.1_3 or newer where the fix is included. Configure receive.maxInputSize in the repository config to a reasonable limit to prevent excessive memory allocation. Until patched, restrict push access to trusted authenticated clients only or disable push functionality if not needed. Additionally, apply OS-level memory limits (e.g., ulimit, cgroups, or container memory limits) to contain potential memory exhaustion from malicious pushes.

Description

CVE-2026-47734 is a denial-of-service vulnerability in Dulwich-based Git servers that accept pushes. An attacker with push access can send a crafted thin pack with a maliciously large declared delta size, causing the server to allocate excessive memory and potentially exhaust system resources. This affects servers exposing git-receive-pack functionality via Dulwich. The issue is patched in Dulwich version 1.2.5 and later.

Impact

An attacker with push access can cause a denial-of-service condition by exhausting server memory through a crafted git push. This impacts availability of Dulwich-based Git servers that accept pushes. There is no impact on confidentiality or integrity reported. The CVSS v3.1 score is 5.7 (medium severity) reflecting network attack vector, low complexity, requiring privileges and user interaction, and causing availability impact only.

Summary

This vulnerability involves uncontrolled resource consumption due to unbounded memory allocation when Dulwich processes a crafted thin pack during a git push. The attacker controls the delta header's declared destination size, causing Dulwich's add_thin_pack and apply_delta functions to allocate hundreds of megabytes of memory disproportionate to the actual data received. This can lead to memory exhaustion and denial of service on servers running Dulwich-based git-receive-pack services. The vulnerability affects versions >=1.2.0 and <2.4.1_3 and is fixed in version 2.4.1_3. The fix introduces a max_input_size parameter to limit input size and prevent excessive memory allocation.

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Affected software

Description

AI analysisMachine-generated, updated 30 Oct 2026, 08:17 UTC

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