PAGES
← all tools
◆ General Utilities & Libraries

gss-ntlmssp

v1.2.0 open-source

GSS-NTLMSSP is a mechglue plugin for the GSSAPI library that implements NTLM authentication.

source ↗ rss ↗ What is a cyber toolchain? last repo push Oct 30, 2026

Summary

gss-ntlmssp is an open-source mechglue plugin for the GSSAPI library that implements NTLM authentication, and it is free to use. It runs as a library loaded into the GSSAPI stack rather than as a standalone program, built and tested specifically against the libgssapi implementation shipped with MIT KerberosKerberosA network authentication protocol that uses tickets issued by a trusted service. Users and services can prove their identities without sending a password to each application. 1.11 and later. This puts it in the hands of systems programmers and administrators who need NTLM as a fallback mechanism where Kerberos authentication is not available or not viable, rather than application developers working at a higher level. It sits in the authentication-mechanism category alongside other GSSAPI plugins, with no competing product named in its own documentation. First committed in 2013 and still drawing contributions from 18 people, it has slowed to 5 commits in the past year and its last release was over two and a half years ago.

GSS-NTLMSSP is a mechglue plugin for the GSSAPI library that implements NTLM authentication.

How gss-ntlmssp helps

Can an application still authenticate a client when Kerberos is not available on the network?

negotiates NTLM through the standard GSSAPI calls the application already makes, so code written against GSSAPI gets a working credential exchange without a Kerberos ticket

Will a service that only understands GSSAPI calls be able to talk to an NTLM-only client?

translates the NTLM message exchange (negotiate, challenge, authenticate) into the GSSAPI security context model the calling application expects

Which authentication mechanism is actually being negotiated when a connection falls back from Kerberos?

registers its own OID in the mechanism space donated for this purpose, so the mechglue layer can identify and select NTLM distinctly from Kerberos at negotiation time

Is a given NTLM implementation compatible with what Windows clients and servers actually send on the wire?

follows the MS-NLMP protocol documentation for message structure, so the exchange matches what Samba and Windows peers produce rather than a reimplementation guessed from scratch

all 4 features, with the evidence for each →

Languages

English, Chinese (Traditional), Indonesian, Korean, Russian, Turkish Interface: English, Chinese (Traditional), Indonesian, Korean, Russian, Turkish · Release notes: Korean Korean added in v1.1.0 (Apr 1, 2022)

Features

4 capabilities

Built from gss-ntlmssp's releases, docs, README and our own runs. “Seen” marks the month we first spotted a release the vendor didn't date. Group names and tags are our labels.

Compare with peers →

What gss-ntlmssp offers you

  • Plugin API support1
  • Plugin system1
All capabilities 4 capabilities
NTLM authentication support via MIT Kerberos libgssapi shipped Implements NTLM authentication as a GSSAPI mechglue plugin for the MIT Kerberos libgssapi library. 2 releases · 1 other source · first seen Feb 2023

Also counts toward: Plugin API support, Plugin system

release

  • Allows gss_wrap to proceed even when NEGOTIATE_SEAL was not negotiated in the context v1.2.0 · Feb 2023 · source · release history
  • Adds the gss_set_cred_option function to allow setting credential options at runtime v1.2.0 · Feb 2023 · source · release history

docs

  • GSSAPI mechglue plugin implementing NTLM authentication for MIT Kerberos libgssapi.
GSS_C_MA_NOT_DFLT_MECH flag handling shipped Drops support for the GSS_C_MA_NOT_DFLT_MECH flag. 1 release · first seen Apr 2020

release

Mechanism attribute querying shipped Queries mechanism attributes via gss_inquire_attrs_for_mech(). 1 release · first seen Apr 2020

release

  • Adds gss_inquire_attrs_for_mech() function for querying mechanism attributes. v0.9.0 · Apr 2020 · source · release history
Session key exposure shipped Retrieves the session key during the security context establishment process. 1 release · first seen Apr 2020

release

  • Enables retrieving the session key during the security context establishment process. v0.9.0 · Apr 2020 · source · release history

Lines in monospace are the tool's own words: help text parsed from its source, or an endpoint from its API document. Under release, a line is our summary of a dated release. Under docs, it is quoted from the tool's own documentation or website. Each links back to the source it came from.

Score card

  1. Shipping velocity releases a month, last 12 months
  2. Documentation quality release-notes rubric, 0–100
  3. Breaking-change discipline how rarely a release breaks users, and notice given
  4. Maintenance risk quiet time against its own cadence, maintainers
  5. Innovation & surface new capabilities, API and MCP surface
  6. Community health
  7. Contributor trend distinct committers, this year against last
  8. Maintainer concentration bus factor now against a year ago
  9. Issue backlog trend issues closed per issue opened, 12 months
  10. Responsiveness median time to a maintainer’s first reply

Nine scores for gss-ntlmssp, each built from the releases, notes and API history this site tracks — and, on Researcher and Business, where it stands among every measured tool in its category and how that has moved.

Score cards are part of every paid plan.

See plans →

Each score is 0–100 on a published rubric, derived from data this site already shows. A dimension we cannot measure says so — it is never scored 0 and never enters a rank.

How this is scored
  • Shipping velocity — releases a month over the last 12 months, on a log scale where 16 a month scores 100. Needs 3 releases in the window.
  • Documentation quality — the release-notes rubric published on the analytics page, unchanged.
  • Breaking-change discipline — the share of releases carrying a breaking change (none scores 100, half or more scores 0). Only projects that label breaking changes are measured: a clean record cannot be told from an unlabelled one.
  • Maintenance risk — quiet time measured against the tool's own release cadence (quiet longer than 90 days and three typical gaps scores 0), plus the number of active maintainers and whether contributors are growing, where known. Higher is lower risk.
  • Innovation & surface — new capabilities in the feature ledger this year, API and MCP operations added, and the share of commits that are features: the mean of whichever we hold.
  • Community health (open-source tools only) — each is a direction, not a size: contributors this year against last, the bus factor now against a year ago, and issues closed per issue opened, where steady scores 50, doubled 100 and halved 0; plus the median time to a maintainer's first reply (an hour scores about 100, a month or more 0). A commercial card has no repository and carries none of the four.
  • Documented delivery (commercial tools) — when a vendor's documented new capabilities have slowed against its own baseline, that counts against the overall standing as heavily as two low dimensions. Steady delivery, or too little history to judge, leaves the standing alone; it is never a sixth score.
  • Open-source tools are scored on repository signals; commercial tools on their published changelog. Ranks compare tools within one category and one profile and need at least five measured peers; the overall standing needs three ranked dimensions. Best-in-breed or consolidator is a shape, not a quality, and is never scored.

Release-note detail over time

See how much detail gss-ntlmssp puts in its release notes, quarter by quarter, and compare it with tracked tools in the same category. This history uses up to ten retained, reviewed notes per tool; sparse or blank older quarters may reflect that limit.

Checking release-note history…

Explore the full chart →

Releases

Show

4 entries

  1. February 20233
  5. April 20201
    Show

    4 entries

    1. v1.2.0 Feb 12, 2023 · release notes

      gss-ntlmssp v1.2.0 adds gss_set_cred_option API and relaxes gss_wrap seal negotiation requirement.

      └──▷ GET THIS VERSION 
      $ git clone --branch v1.2.0 https://github.com/gssapi/gss-ntlmssp.git
# already have the repo? check out this version:
$ git checkout v1.2.0
      • Adds the gss_set_cred_option function to allow setting credential options at runtime
      • Allows gss_wrap to proceed even when NEGOTIATE_SEAL was not negotiated in the context

      2 details in Everything

    2. advisory CVE-2023-25566 Feb 12, 2023 · issue 128
      • CVE-2023-25566: Memory leak when parsing usernames (CVSSCVSSCommon Vulnerability Scoring System, a method for describing a vulnerability's characteristics and severity. Its score is not the probability that attackers will exploit it. 7.5, affects <= 1.1.0)⁠︀︄︇︀︅︉︀︅︀︀︃︀︀︅︅︀︅︊︀︄︆︀︃︄⁠
    3. advisory CVE-2023-25567 Feb 12, 2023 · issue 128
      • CVE-2023-25567: Out-of-bounds read when decoding target information (CVSSCVSSCommon Vulnerability Scoring System, a method for describing a vulnerability's characteristics and severity. Its score is not the probability that attackers will exploit it. 7.5, affects <= 1.1.0)⁠︀︄︇︀︅︉︀︅︀︀︃︀︀︅︅︀︅︊︀︄︆︀︃︄⁠
    4. v0.9.0 Apr 29, 2020 · release notes

      gss-ntlmssp v0.9.0 adds session key retrieval and new GSS-API inquiry API

      └──▷ GET THIS VERSION 
      $ git clone --branch v0.9.0 https://github.com/gssapi/gss-ntlmssp.git
# already have the repo? check out this version:
$ git checkout v0.9.0
      • Adds gss_inquire_attrs_for_mech() function for querying mechanism attributes.
      • Enables retrieving the session key during the security context establishment process.

      2 details in Everything

      └──▷ BREAKING ON UPGRADE
      • !Drops support for GSS_C_MA_NOT_DFLT_MECH flag.

    Project health

    Issue, contributor and maintainer activity in gssapi/gss-ntlmssp, 2023-10 – 2026-09, as of 2026-09-25. Twelve-month figures first; the trend lines run the whole window.

    1. Contributors 5 +5 vs prior 12 months
    2. Maintainers 1 +1 joined · −0 left, last 12 months
    3. Bus factor 1 committers behind half the commits
    4. Community-filed 100% of issues opened, last 12 months
    5. Median time to close not measured first maintainer reply 0.3 hours
    6. Open backlog 10 of 47 issues ever filed
    1. Issues opened / month 0 · 0 communitymaintainers
    2. Open backlog 10
    3. Contributors / month 2
    4. Commits / month 3
    5. Stars 42
    Issue themes, last 12 months
    • other 100%

    Counts from the project's public repository and git history; no individuals are identified. Maintainers are the committers covering 80% of the last year's commits. how we measure this

    Libraries its release ships

    What its latest release locks, checked against known advisories.

    None of its release's images build from a lockfile we can read.

    Add the badge to your README

    Maintain this project? The badge links readers straight to this page, so they can follow every release here.

    Tracked by Cyber Toolchain Choose a badge style and copy the code →
    compare.md

      Free the public facts, no sign-in Any paid plan all other sections Researcher & Business pricing history and category rank

      my-toolchain — 0 tools

        Betas, release candidates and previews. Turn it off to see final releases only. It also applies to changes you ask for over MCP when you're signed in.
        browse all tools → score card for your toolchain →
        cyber-toolchain / feedback

        Send us feedback