CVE
AutoMapper denial of service via MaxDepth bypass in object mapping
AutoMapper versions before 15.1.4 and 16.0.0 before 16.3.0 are affected in polymorphic maps, runtime-typed members, nested dictionary sources and recursive converters. Fixed in 15.1.4 and 16.3.0.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Exploited
- No known exploitation
- Fix
- Fixed in 16.3.0, 15.1.4
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 16.3.0, 15.1.4.
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- FIRST's estimate of the chance attackers exploit it in the next 30 days, updated daily.What do these mean? →
- 0.55% · 46th percentile
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 35/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
AutoMapper, a .NET object-to-object mapping library from LuckyPennySoftware, can be made to recurse without its MaxDepth limit when it maps certain polymorphic, runtime-typed, or recursive data. An attacker can reach this remotely, without logging in, by sending deeply nested input that crashes the process and takes it down.
Original description
AutoMapper is a convention-based object-object mapper in .NET. Prior to 15.1.4 and from 16.0.0 until 16.3.0, AutoMapper can recurse without an effective MaxDepth limit when mapping polymorphic graphs through Include or IncludeBase, runtime-typed object or interface members, nested Dictionary<string, object> or ExpandoObject sources, or recursive ConvertUsing type converters. Deep attacker-influenced graphs on these paths can throw an uncatchable StackOverflowException and terminate the process. This issue is fixed in versions 15.1.4 and 16.3.0.
Who should check
Teams on AutoMapper 15.x before 15.1.4 or 16.x before 16.3.0 that map untrusted deep data via Include/IncludeBase, object members, dictionaries or ExpandoObject.
“Polymorphic maps: derived type maps ( Include / IncludeBase ) didn't inherit the base map's MaxDepth”
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure17/25No login or user action needed, reachable over the network without a login · Unknown: Advisories don't say whether default setups are affected
- Reach10/20Affects NuGet packages
- Severity7.5/10CVSS 7.5
- No patch0/5No signal
What would change the score
- Would score about 80 if added to CISA KEV
- Would score about 75 if CISA's SSVC rates exploitation active
- Would score about 40 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 16.3.0, 15.1.4.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-128081 (AutoMapper: Denial of Service via uncontrolled recursion that bypasses MaxDepth), using the cve.now data below.
Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.
What cve.now has for CVE-2026-128081 (entry last updated 2026-11-13):
Affected:
- LuckyPennySoftware AutoMapper: from 16.0.0, fixed in 16.3.0; fixed in 15.1.4
- NuGet package AutoMapper: from 16.0.0, fixed in 16.3.0
- NuGet package AutoMapper: fixed in 15.1.4
Fixed versions: 16.3.0, 15.1.4.
Conditions (all must be true for the bug to be hit):
- Polymorphic maps using Include or IncludeBase (source: https://github.com/LuckyPennySoftware/AutoMapper/security/advisories/GHSA-gpwp-5797-mjff)
- Members typed as object or an interface (source: https://github.com/LuckyPennySoftware/AutoMapper/security/advisories/GHSA-gpwp-5797-mjff)
- Nested Dictionary<string, object> or ExpandoObject sources (source: https://github.com/LuckyPennySoftware/AutoMapper/security/advisories/GHSA-gpwp-5797-mjff)
- Recursive ConvertUsing type converters that call context.Mapper.Map (source: https://github.com/LuckyPennySoftware/AutoMapper/security/advisories/GHSA-gpwp-5797-mjff)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: network access, no login, no user action.
CISA KEV: CVE-2026-128081 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-128081 only. If you also check another CVE, look up its own KEV status; never assume it from this one.
How to check:
- Packages (NuGet): find every lockfile in each project and run the stack.check operation of the cve.now MCP server (execute) on each one. Compare the resolved versions, not the ranges a manifest declares, with the affected versions above. Include transitive dependencies.
Verify against the linked advisories before concluding, and cite the date you read each one:
- https://github.com/LuckyPennySoftware/AutoMapper/security/advisories/GHSA-gpwp-5797-mjff
- https://github.com/LuckyPennySoftware/AutoMapper/commit/aee81b50574c3c7005283cca2b2396e295bd8ed9
- https://github.com/LuckyPennySoftware/AutoMapper/commit/bdbbf5967d20d28e611ab65de1d96d1047a95ab9
- https://github.com/LuckyPennySoftware/AutoMapper/releases/tag/v15.1.4
- https://github.com/LuckyPennySoftware/AutoMapper/releases/tag/v16.3.0
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.
Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.
Entry: https://cve.now/CVE-2026-128081
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-128081"}.Timeline
- CVE published
- First seen by cve.now
Affected versions
- LuckyPennySoftware AutoMapper
From 16.0.0 · fixed in 16.3.0; fixed in 15.1.4
- AutoMapperNuGet
From 16.0.0 · fixed in 16.3.0
Fixed in 16.3.0 (released Nov 5, 2026, 8 days before disclosure).
- AutoMapperNuGet
fixed in 15.1.4
Fixed in 15.1.4 (released Nov 5, 2026, 8 days before disclosure).
The latest release, 17.0.0, is not affected.
Evidence 7
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Advisory
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-128081
Is CVE-2026-128081 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
Deeply nested data mapped through certain AutoMapper paths recurses without the MaxDepth limit being applied, which overflows the stack. The process crashes with an uncatchable StackOverflowException, causing denial of service.Source: github.com
Which versions are affected by CVE-2026-128081?
AutoMapper: from 16.0.0 before 16.3.0; before 15.1.4. AutoMapper (NuGet): from 16.0.0 before 16.3.0. AutoMapper (NuGet): before 15.1.4.Source: cve.now feed data
Am I affected, and how do I check?
AutoMapper before 15.1.4, and 16.0.0 up to but not including 16.3.0. The risky setups are polymorphic maps using Include or IncludeBase, members typed as object or an interface, mapping nested Dictionary<string, object> or ExpandoObject sources onto typed destinations, and ConvertUsing converters that call context.Mapper.Map. To check a project, look at the AutoMapper package version in its project file or in the output of dotnet list package.Source: github.com
How do I fix CVE-2026-128081?
Upgrade AutoMapper to 16.3.0 on the 16.x line or to 15.1.4 on the 15.x line.Source: github.com