Integer underflow in the BowserWriteErrorLogEntry function in the Common Internet File System (CIFS) browser service in Mrxsmb.sys or bowser
Integer underflow in the BowserWriteErrorLogEntry function in the Common Internet File System (CIFS) browser service in Mrxsmb.sys or bowser.sys in Active Directory in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP1 and SP2, Windows Server 2008 Gold, SP2, R2, and R2 SP1, and Windows 7 Gold and SP1 allows remote attackers to execute arbitrary code or cause a denial of service (system crash) via a malformed BROWSER ELECTION message, leading to a heap-based buffer overflow, aka "Browser Pool Corruption Vulnerability." NOTE: some of these details are obtained from third party information.
- Published
- Feb 15, 2011
- Updated
- Jun 16, 2026
- EPSS
- 68.1% · 99th percentile
- CWE
- CWE-119
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Action score
60
This week
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- CVSS
- 40 / 40 · 10.0 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 20 / 30 · 68.1%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| microsoft | windows 2003 server | cpe:2.3:o:microsoft:windows_2003_server |
| microsoft | windows server 2003 | cpe:2.3:o:microsoft:windows_server_2003 |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- microsoft windows server 2003all versions
Same product
microsoft: all recordsOther highest-scoring records for the same primary product.
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Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
Weaponized
A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.
Evidence
- Metasploit module ×1
- Exploit-DB entry ×1
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Exploit-DB entry | dos | 2011-02-14 |
| Metasploit module | auxiliary/dos/windows/smb/ms11_019_electbowserMicrosoft Windows Browser Pool DoSauxiliary | — |
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- First PoC-2 d
- Published
- TodaySep 30, 2026+5705 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- C · data can be read
- Integrity
- C · data or configuration can be modified
- Availability
- C · the service can be disrupted
- Attack complexity
- Low
- Confidentiality impact
- C
- Integrity impact
- C
- Availability impact
- C
Weakness class (CWE)
CWE-119 · Improper Restriction of Operations within the Bounds of a Memory BufferCVSS vector
AV:N/AC:L/Au:N/C:C/I:C/A:C
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Overflow BuffersCAPEC-100likelihood: High · Very High
- Buffer ManipulationCAPEC-123likelihood: High · Very High
- Client-side Injection-induced Buffer OverflowCAPEC-14likelihood: Medium · High
- Filter Failure through Buffer OverflowCAPEC-24likelihood: High · High
- MIME ConversionCAPEC-42likelihood: High · High
- Overflow Binary Resource FileCAPEC-44likelihood: High · Very High
- Buffer Overflow via Symbolic LinksCAPEC-45likelihood: High · High
ATT&CK techniques
—
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
- archives.neohapsis.com/archives/fulldisclosure/2011-02/0284.html
- blogs.technet.com/b/mmpc/archive/2011/02/16/my-sweet-valentine-the-cifs-browser-protocol-heap-corruption-vulnerability.aspx
- blogs.technet.com/b/srd/archive/2011/02/16/notes-on-exploitability-of-the-recent-windows-browser-protocol-issue.aspx
- secunia.com/advisories/43299
- www.kb.cert.org/vuls/id/323172
- www.securitytracker.com/id?1025328
- www.us-cert.gov/cas/techalerts/TA11-102A.html
- www.vupen.com/english/advisories/2011/0394
- www.vupen.com/english/advisories/2011/0938
- docs.microsoft.com/en-us/security-updates/securitybulletins/2011/ms11-019
- exchange.xforce.ibmcloud.com/vulnerabilities/65376
- oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A12637
Vendor advisories and official records. Exploit/PoC links are deliberately left out.