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CVE Record

CVE-2019-11046: Buffer underflow in bc_shift_addsub

In PHP versions 7.2.x below 7.2.26, 7.3.x below 7.3.13 and 7.4.0, PHP bcmath extension functions on some systems, including Windows, can be tricked into reading beyond the allocated space by supplying it with string containing characters that are identified as numeric by the OS but aren't ASCII numbers. This can read to disclosure of the content of some memory locations.

LowCVSS 3.7Not KEV-listedUpdated
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Glexia's TakeAutomated analysislow

Security readout for executives and security teams

Plain-English summary

This is a low-severity PHP bcmath memory disclosure issue. An attacker who can get specially classified numeric-looking strings processed by affected bcmath functions may cause PHP to read small amounts of memory beyond an allocated buffer. The public record does not show active exploitation.

Executive priority

Treat this as routine patch management unless affected PHP bcmath is exposed in critical internet-facing applications. It is not a crisis-level CVE based on the supplied evidence, but stale PHP versions should be cleaned up.

Technical view

CVE-2019-11046 is a CWE-125 out-of-bounds read in PHP bcmath, specifically bc_shift_addsub. Affected versions are PHP 7.2.x before 7.2.26, 7.3.x before 7.3.13, and 7.4.0. The issue depends on OS numeric character classification, including Windows, and has high attack complexity.

Likely exposure

Exposure is most likely on legacy PHP systems running the bcmath extension where untrusted input can reach bcmath operations. Systems on patched vendor PHP packages or PHP versions outside the listed affected ranges are less likely exposed.

Exploitation context

The CVSS vector is network-accessible with no privileges or user interaction, but high complexity and limited confidentiality impact. The provided sources and KEV status do not support active exploitation claims.

Researcher notes

Evidence supports a bounded confidentiality issue in PHP bcmath with OS-dependent input handling. The source bundle does not provide exploit proof, active exploitation evidence, or broad impact beyond affected PHP and vendor-distributed packages.

Mitigation direction

  • Upgrade PHP to vendor packages addressing CVE-2019-11046.
  • Move PHP 7.4.0 systems to a fixed vendor-supported release.
  • Prioritize internet-facing applications using the bcmath extension.
  • Check OS and appliance vendor advisories for backported fixes.
  • Retire unsupported PHP branches where practical.

Validation and detection

  • Inventory PHP versions across servers, containers, and appliances.
  • Confirm whether the bcmath extension is installed and enabled.
  • Review package changelogs or vendor advisories for CVE-2019-11046.
  • Identify application paths passing untrusted input to bcmath functions.
  • Run authenticated vulnerability scanning against PHP packages.
Prepared
Confidence
high
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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cwe · low confidence lookup

CWE-125: Exact CWE lookup

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cve · low confidence lookup

CVE-2019-11046 mapping review

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Vulnerability profileCVE Program record
Severity
Low
CVSS
3.7 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
14Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
3.7CVSS 3.1LowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N2.21.4Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

3.7Low
CVSS 3.1 vector shape for CVE-2019-11046Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
PHP GroupPHP7.2.x, 7.3.x, 7.4.xListed
Weakness

CWE details

CWE-125

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-125 · source CWE mapping

Out-of-bounds Read

Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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