CVE-2026-44167Network attack vector

Service interruption via oversized ASN.1 OID amplification

Published May 12, 2026 · Updated May 12, 2026

Resource exhaustion in phpseclib before 1.0.29, 2.0.54, and 3.0.52 allows remote attackers to interrupt service via untrusted ASN.1 data. ASN1::_decodeOID() accepts encoded object identifiers as long as 4,096 bytes, allowing base-128 OID components to amplify into costly large-number decoding. Reachability requires an application to pass attacker-controlled X.509 certificates, PKCS#8 keys, or other ASN.1 content to the library, where resource exhaustion interrupts the hosting service.

CVSS severity7.5
High
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in phpseclib before 1.0.29, 2.0.54, and 3.0.52 allows remote attackers to interrupt service via untrusted ASN.1 data. ASN1::_decodeOID() accepts encoded object identifiers as long as 4,096 bytes, allowing base-128 OID components to amplify into costly large-number decoding. Reachability requires an application to pass attacker-controlled X.509 certificates, PKCS#8 keys, or other ASN.1 content to the library, where resource exhaustion interrupts the hosting service.

The record

CVE
CVE-2026-44167
Published
May 12, 2026
Updated
May 12, 2026
Vendor
phpseclib
Product
phpseclib
Classifications
CWE-400, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 12, 2026CVE publishedPublication date reported by the CVE source.
  2. May 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 0.1.1, < 1.0.29
  2. Affected versionversion=>= 2.0.0, < 2.0.54
  3. Affected versionversion=>= 3.0.0, < 3.0.52

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

phpseclib · phpseclibversion=>= 0.1.1, < 1.0.29; version=>= 2.0.0, < 2.0.54; version=>= 3.0.0, < 3.0.52

Published CVSS scores

7.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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