CyberSecBulletin
CVE-2026-109618Exploited in the wildNVD status: Analyzed

PHP Memory Corruption

Published Updated By the CyberSecBulletin desk

CVE-2026-109618 is a critical-severity use after free vulnerability in PHP from PHP Group, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 8.2.35, 8.3.36, 8.4.27 as the first without the flaw, so updating PHP to one of those releases or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on October 26, 2026, which means attacks have been observed in the wild.

Patch now

Attackers are already exploiting this vulnerability, according to CISA.

What to do

  1. Update PHP to 8.2.35 or 8.3.36 or 8.4.27 or 8.5.12, whichever matches your release line, or a later version.
  2. Update Local Monitoring bt-monitoring-vm to V20261103 or a later version.
  3. CISA's required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
  4. Read the advisory on github.com for workarounds and exact fixed builds.
  5. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
PHP GroupPHP8.2.* up to, but not including, 8.2.35; 8.3.* up to, but not including, 8.3.36; 8.4.* up to, but not including, 8.4.27; 8.5.* up to, but not including, 8.5.128.2.35, 8.3.36, 8.4.27, 8.5.12
SiemensAMIS TSall versionsNot stated
SiemensAX4Not specified in the recordNot stated
Siemensblueplanet 360 NX3 M6 WM OD IISXall versionsNot stated
Siemensblueplanet 360 NX3 M6 WM OD IISX - Sall versionsNot stated
SiemensBuilding XNot specified in the recordNot stated
SiemensCADRANot specified in the recordNot stated
SiemensCall stationsNot specified in the recordNot stated
SiemensCapitalNot specified in the recordNot stated
SiemensChargesightNot specified in the recordNot stated
SiemensClimatix Cloud ICNot specified in the recordNot stated
SiemensClimatix DevicesNot specified in the recordNot stated
SiemensConnect InsightsNot specified in the recordNot stated
SiemensConnect X200Not specified in the recordNot stated
SiemensConnect X300Not specified in the recordNot stated
SiemensConnect X500Not specified in the recordNot stated
SiemenscRSPNot specified in the recordNot stated
SiemensDepotfinityNot specified in the recordNot stated
SiemensDesigncenterNot specified in the recordNot stated
SiemensDesigncenter XNot specified in the recordNot stated
SiemensDesigncenter X EssentialsNot specified in the recordNot stated
SiemensDesigo CCNot specified in the recordNot stated
SiemensDesigo DXR2Not specified in the recordNot stated
SiemensDesigo DXR3Not specified in the recordNot stated
SiemensDesigo OpticNot specified in the recordNot stated

Version data comes from the organisation that assigned the CVE; 35 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 4.09.2CriticalCNA (php.net)
CVSS 3.19.8CriticalNVD

Official description

PHP uses longjmp() for out-of-memory (OOM) errors to exit the current context and abort handling of the request. Some contexts may not properly account for this scenario and leave request memory in an uninitialized state before performing an allocation. The subsequent request cleanup procedure may read or branch on this memory. Multiple OOM strategies can consistently trigger this condition and lead to remote code execution (RCE).

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

How developers prevent this class of flaw

  • Choose a language that provides automatic memory management.
  • When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.

More Use After Free vulnerabilities (CWE-416)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
  3. Added to CISA's Known Exploited Vulnerabilities catalogue.
  4. Deadline for US federal agencies to remediate, set by CISA.
  5. Record last changed materially (score, affected products, status or references).

References

Other references

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