Topic: Crashes in libhttpd.dll with 2.4.69 [with LDAP Auth]

[mikejs]

Hi,

I have a few windows servers that run Apache, some with PHP (8.5.11).

All has been working fine for many versions, but with the 2.4.69 release we're having problems.

The service starts, but once it receives a request, it crashes in libhttpd.dll.

These crashes result in this repeating error in the error.log:

[Fri Oct 02 13:45:55.228043 2026] [mpm_winnt:notice] [pid 1632:tid 340] AH00455: Apache/2.4.69 (Win64) OpenSSL/3.5.9 configured -- resuming normal operations
[Fri Oct 02 13:45:55.228043 2026] [mpm_winnt:notice] [pid 1632:tid 340] AH00456: Apache Lounge VS18 Server built: Oct 1 2026 09:34:06
[Fri Oct 02 13:45:55.228043 2026] [core:notice] [pid 1632:tid 340] AH00094: Command line: 'C:\\Apache24\\bin\\httpd.exe -d C:/Apache24'
[Fri Oct 02 13:45:55.228043 2026] [mpm_winnt:notice] [pid 1632:tid 340] AH00418: Parent: Created child process 4824
[Fri Oct 02 13:45:55.821707 2026] [mpm_winnt:notice] [pid 4824:tid 360] AH00354: Child: Starting 150 worker threads.
[Fri Oct 02 13:45:58.102990 2026] [mpm_winnt:notice] [pid 1632:tid 340] AH00428: Parent: child process 4824 exited with status 3221225477 -- Restarting.


A single request causes a cascade of these - I think 8 of them.


The key bit there being "exited with status 3221225477", which in hex is 0xC0000005, which is a pretty generic error. Difficult to know what it points to, and difficult to search on as there are a lot of posts about it, and clearly a lot of possible cases that result in that error.


At the same time you get crash details in Event Viewer:

Faulting application name: httpd.exe, version: 2.4.69.0, time stamp: 0x6abe0d7f
Faulting module name: libhttpd.dll, version: 2.4.69.0, time stamp: 0x6abe0cfa
Exception code: 0xc0000005
Fault offset: 0x000000000001dbc8
Faulting process id: 0x15d8
Faulting application start time: 0x01dd5277c9dce2c9
Faulting application path: C:\Apache24\bin\httpd.exe
Faulting module path: C:\Apache24\bin\libhttpd.dll
Report Id: ff945d4d-434d-4985-83c7-ba7a4bb08e80
Faulting package full name:
Faulting package-relative application ID:

Does the fault offset point to anything more specific?

Anything useful we can do with the resulting .dmp files?

Commenting out PHP from the config does not fix it.

Rolling everything back to 2.4.68 does fixes it, but clearly not a long term solution.

I started from scratch with the httpd.conf as supplied with 2.4.69 in case there were any differences there - same problem.

I've also experimented with mixing and matching, and found that having everything from 2.4.69, but copying the modules folder from from 2.4.68 works with no issues.

So it looks more like it's a 2.4.69 module rather than the main binaries themselves?

This is the list of modules we're loading, in order:

mod_access_compat
mod_allowmethods
mod_auth_basic
mod_authn_core
mod_authn_file
mod_authnz_ldap
mod_authz_core
mod_authz_groupfile
mod_authz_host
mod_authz_user
mod_socache_shmcb
mod_filter
mod_reqtimeout
mod_autoindex
mod_cgi
mod_mime
mod_ldap
mod_log_config
mod_alias
mod_dir
mod_env
mod_headers
mod_setenvif
mod_version

Anyone else seeing this kind of thing with 2.4.69?

Suggestions as to what to try next?

Thanks,

Mike

[Otomatic]

Hi,

# The ThreadStackSize directive sets the size of the stack (for autodata)
# of threads which handle client connections and call modules to help process
# those connections. In most cases the operating system default for stack size
# is reasonable, but there are some conditions where it may need to be adjusted.
# Apache httpd may crash when using some third-party modules which use a
# relatively large amount of autodata storage or automatically restart with
# message like: child process 12345 exited with status 3221225725 -- Restarting.
# This type of crash is resolved by setting ThreadStackSize to a value higher
# than the operating system default.
ThreadStackSize 8388608

[James Blond]

a 0xC0000005 is an access violation. How do you run your apache? As a service? What user is set in the service settings?

What do you see in the windows event log about this?

[mikejs]

Hi,

Been trying to narrow down the problem, and I think I'm getting somewhere.

In short, I can get a 2.4.69 install working by copying over just the mod_authnz_ldap.so file from 2.4.68.

So, superficially, it looks like there might be a problem with that module in 2.4.69, on windows.

Does that shed any more light on the problem? I can just roll that one file back on our servers, but I'd prefer to know what the underlying issue is with that file.

We're not doing anything knowingly weird or complicated with LDAP auth, just stuff like:

[Stanicher]

Same here. Running serveral PHP apps on a windows server with 2.4 since months without any problems. With 2.4.69 there is an issue with one of these PHP apps.

The error is the same as stated:

[Wed Oct 07 12:21:33.830471 2026] [mpm_winnt:notice] [pid 22676:tid 476] AH00455: Apache/2.4.69 (Win64) OpenSSL/3.5.9 PHP/8.5.11 configured -- resuming normal operations
[Wed Oct 07 12:21:33.830908 2026] [mpm_winnt:notice] [pid 22676:tid 476] AH00456: Apache Lounge VS18 Server built: Oct 1 2026 09:34:06
[Wed Oct 07 12:21:33.830908 2026] [core:notice] [pid 22676:tid 476] AH00094: Command line: 'C:\\Apache24\\bin\\httpd.exe -d C:/Apache24'
[Wed Oct 07 12:21:33.836743 2026] [mpm_winnt:notice] [pid 22676:tid 476] AH00418: Parent: Created child process 8560
[Wed Oct 07 12:21:34.628043 2026] [mpm_winnt:notice] [pid 8560:tid 484] AH00354: Child: Starting 1920 worker threads.
[Wed Oct 07 12:23:14.682066 2026] [mpm_winnt:notice] [pid 22676:tid 476] AH00428: Parent: child process 8560 exited with status 255 -- Restarting.

These are the current findings:

1.
This issue only occurs on one php app. All other stuff on the server is running fine.

2.
The issue appears both via http and https.

3.
The app in question is doing a basic-authentication. Provider is LDAP, users are in an active directory domain. Other php app doing LDAP authentication against that very same AD domain are not affected.

4.
It does not matter what browser or tool you use. Even curl won't work (connection reset after httpd restarted).

5.
It also does not matter if you use IPv4, IPv6, over the network or on the server itself on 127.0.0.1.

6.
The issue does NOT occur if authentication fails due to incorrect credentials. In that case a 401 is logged in the access log.

7.
The issue only occurs if the authentication is fine (correct username and password). In that case, httpd crashes before logging anythin in the access.log.

8.
Returning to 2.4.68 with the very same config files resolves the issue.

9.
Placing a static html file in the php apps directory and calling its URL doesn't work either. Once you authenticated, it crashes. So obviously it has nothing to do with php.

To make things even more complicated: There are currently 14 users in the AD-group permitted to this php app. Four of them have the issue and can't use the app any more. The other ten can authenticate and the app works fine.

Increasing Thread Stack does not help.

No matter if running as a service or running on the command line.

I've got no more ideas...

[mikejs]

Glad to know it's not just me...

Have you tried 2.4.69 with the mod_authnz_ldap.so from 2.4.68?

Also, in our environment, commenting out PHP doesn't help either (which makes sense as it's failing before getting to the point where php would be invoked).

[Stanicher]

Yep. 2.4.69 with mod_authnz_ldap.so from 2.4.68 works fine. Great hint. Thanks!

[admin]

I reported to the httpd developers.

[Steffen]

Replaced in the download the 68 one

Thanks for the reports !