CVE-2026-55380VulnerabilityPublished 6 Jul 2026Updated 4 Nov 2026

Pillow: Prior to 12.3.0, PIL/GdImageFile.py GdImageFile._open() read image dimensions from the GD 2.x header and

Affects pillowSource GCVE Database

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Authoritative record:CVE-2026-55380· High 7.5

Not known to be exploited · CVSS 7.5 High · fixed in 12.3.0 : patch pillow soon.

Data as of 5 Nov 2026, 00:01 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 0.5% chance of exploitation in 30 days – higher than 44% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 12.3.0

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 6 Jul 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 4 Nov 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

Affected software

Product	Affected	Fixed in
Ubuntu 26.04 LTSpillow`pkg:deb/ubuntu/pillow?arch=source&distro=resolute`Other threats	Affected 11.3.0-1ubuntu1 – 12.1.1-2ubuntu1.4 9 affected builds	Fixed in–
Ubuntu 24.04 LTSpillow`pkg:deb/ubuntu/pillow?arch=source&distro=noble`Other threats	Affected 10.0.0-1 – 10.2.0-1ubuntu1.4 8 affected builds	Fixed in–
Ubuntu 22.04 LTSpillow`pkg:deb/ubuntu/pillow?arch=source&distro=jammy`Other threats	Affected 8.1.2+dfsg-0.3 – 9.0.1-1ubuntu0.6 10 affected builds	Fixed in–
Ubuntu Pro 20.04 LTSpillow`pkg:deb/ubuntu/pillow?arch=source&distro=esm-infra/focal`Other threats	Affected 6.1.0-1 – 7.0.0-4ubuntu0.9+esm1 15 affected builds	Fixed in–
Ubuntu Pro 20.04 LTSpillow-python2`pkg:deb/ubuntu/pillow-python2?arch=source&distro=esm-apps/focal`Other threats	Affected 6.2.1-3 – 6.2.1-3ubuntu0.1~esm2 4 affected builds	Fixed in–
Ubuntu Pro 18.04 LTSpillow`pkg:deb/ubuntu/pillow?arch=source&distro=esm-infra/bionic`Other threats	Affected 4.1.1-3build2 – 5.1.0-1ubuntu0.8+esm2 13 affected builds	Fixed in–

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

AI-suggested

Upgrade Pillow to version 12.3.0 or later, where the vulnerability is fixed. No other mitigation is indicated or required.

Description

Pillow, a Python imaging library, had a vulnerability prior to version 12.3.0 where the GD image file loader did not perform a decompression bomb check on image dimensions read from the GD 2.x header. This flaw allowed crafted .gd files to trigger excessive heap memory allocation when loaded. The issue is fixed in Pillow version 12.3.0.

Impact

An attacker can supply a maliciously crafted .gd image file that triggers excessive heap memory allocation when processed by vulnerable Pillow versions. This can cause denial of service by exhausting system memory resources. There is no indication of confidentiality or integrity impact. The CVSS 3.1 score is 7.5 (High), reflecting a network attack vector with no privileges required and no user interaction needed, causing availability impact only.

Summary

The vulnerability in Pillow versions prior to 12.3.0 resides in the PIL/GdImageFile.py module, specifically in the GdImageFile._open() function. This function reads image dimensions from the GD 2.x header and stores them in self._size without invoking the Image._decompression_bomb_check() method. As a result, a specially crafted .gd image file can cause excessive C-heap allocation, potentially leading to denial of service due to resource exhaustion. The flaw is addressed in Pillow 12.3.0 by ensuring the decompression bomb check is performed.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Nov 2026, 21:25 UTC

Technical details

References

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