VulnerabilityPublished 27 May 2026Updated 29 May 2026

CVE-2026-48961: PMQS IO::Compress · Improper Handling of Exceptional Conditions

Affects PMQS IO::CompressSource CVE Database V5

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Not known to be exploited · CVSS 7.3 High : upgrade to 2.220 soon.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

7.3High

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 17% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 2.220

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

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

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: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 27 May 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 30 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 IO::Compress and IO-Compress to 2.220.

Affected software

Product	Affected	Fixed in
PMQSIO::Compress	Affected >=2.207 <2.220	Fixed in 2.220
GitHubIO-Compress`pkg:github/IO-Compress`Other threats	Affected >=2.207 <2.220	Fixed in 2.220

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

AI-suggested

Users should avoid using the zipdetails CLI tool on zip files containing 8-byte UID or GID Info-ZIP Unix Extra Fields until a fix is available. Since the vulnerability does not affect the IO::Compress or IO::Uncompress libraries, library users are not required to take action.

Description

IO::Compress versions from 2.207 before 2.220 for Perl ship a zipdetails CLI tool that crashes with undefined subroutine on Info-ZIP Unix Extra Field with 8-byte UID or GID. When decode_ux() in bin/zipdetails handles an Info-ZIP Unix Extra Field (tag 0x7875) with UID Size or GID Size set to 8, causing zipdetails to decode an 8-byte UID or GID value, it dispatches through decodeLitteEndian(), which calls a misnamed helper unpackValueQ. The actual function defined in the same file is unpackValue_Q (with underscore); the call raises 'Undefined subroutine &main::unpackValueQ' and the script exits with status 255. Library callers of IO::Compress and IO::Uncompress are not affected; the defect is in the bundled CLI tool.

Impact

The impact is limited to denial of service of the zipdetails CLI tool when processing specially crafted zip files containing 8-byte UID or GID Info-ZIP Unix Extra Fields. This may disrupt workflows relying on this tool but does not affect the underlying IO::Compress or IO::Uncompress libraries, nor does it lead to code execution or data corruption. There are no known exploits in the wild.

Summary

The vulnerability in IO::Compress versions 2.207 up to but not including 2.220 involves the zipdetails CLI tool crashing when handling Info-ZIP Unix Extra Fields (tag 0x7875) with UID or GID sizes set to 8 bytes. The crash is triggered by a call to an undefined subroutine 'unpackValueQ' instead of the correctly named 'unpackValue_Q' within the decode_ux() function. This results in the script terminating with exit status 255. Library users of IO::Compress and IO::Uncompress are not impacted by this defect, as it is isolated to the CLI tool.

CWE-755Improper Handling of Exceptional Conditions (opens in a new tab)
Class weaknessLikelihood of exploit: MediumOWASP Top 10 A10:2025: Mishandling of Exceptional Conditions (opens in a new tab)
The product does not handle or incorrectly handles an exceptional condition.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
OWASP Cheat Sheets
Logging (opens in a new tab)
Error Handling (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 3 Jun 2026, 20:42 UTC

WeaknessesCWE-755

Technical details

References

Community reviews

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