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hardened_malloc

13 open-source

hardened_malloc is a security-focused general purpose memory allocator providing the malloc API with substantial hardening against heap corruption vulnerabilities.

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Summary

hardened_malloc is an open-source memory allocator, free to use, that provides the standard malloc API while hardening against heap corruption vulnerabilities such as use-after-free and buffer overflow exploitation. It is built as a drop-in replacement library, loaded via preload for testing or linked into a system's libc setup, rather than run as a standalone program. This puts it in the hands of platform and OS integrators, particularly on Android-based systems where it has custom integration, with glibc and musl covered as well. It descends from and succeeds an earlier hardening effort built on OpenBSD malloc, reusing its general design while dropping the bug-finding focus in favor of pure security hardening. First committed in 2018, the project remains active, with 26 contributors and 87 commits in the past year.

hardened_malloc is a security-focused general purpose memory allocator providing the malloc API with substantial hardening against heap corruption vulnerabilities.

How hardened_malloc helps

Which of my applications are still exploitable through heap corruption bugs like use-after-free or buffer overflows without changing a line of their code?

swaps in a hardened allocator behind the same malloc API, so unsafe heap operations are caught or made unexploitable purely by relinking, with no source changes

Is my program's heap layout predictable enough for an attacker to place data where they want it?

randomizes allocation placement and separates memory into size classes so objects an attacker wants adjacent are far less likely to land together

Which parts of a corrupted heap can I actually inspect after a crash or during debugging?

exposes allocator statistics and API extensions beyond the standard malloc calls, giving visibility into allocation state that a stock allocator does not report

Languages

Not documented

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 hardened_malloc, 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.

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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 hardened_malloc 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.

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Releases

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3 entries

  1. October 20241
  3. August 20241
  5. January 20221
    Show

    3 entries

    1. 13 Oct 14, 2024 · release notes

      hardened_malloc v13 adds ARMARMA family of RISC processor architectures designed by Arm Holdings and licensed to chip makers worldwide; tools target it to run natively on mobile, embedded, and increasingly server and desktop hardware. hardware memory tagging (MTE) support

      └──▷ GET THIS VERSION 
      $ git clone --branch 13 https://github.com/GrapheneOS/hardened_malloc.git
# already have the repo? check out this version:
$ git checkout 13
    2. 12 Aug 6, 2024 · release notes

      hardened_malloc 12 adds self-init disable config and Intel CET support with 32GB class regions on arm64 Android

      └──▷ GET THIS VERSION 
      $ git clone --branch 12 https://github.com/GrapheneOS/hardened_malloc.git
# already have the repo? check out this version:
$ git checkout 12
      • Enables Intel Control-flow Enforcement Technology (CET) support for hardware-enforced control flow integrity

      1 detail in Everything

      └──▷ BREAKING ON UPGRADE
      • !Drops support for legacy compilers and libc versions, requiring modern toolchains at build time
    3. 10 Jan 12, 2022 · release notes

      hardened_malloc v10 adds a configuration variant system with default and light profiles

      └──▷ GET THIS VERSION 
      $ git clone --branch 10 https://github.com/GrapheneOS/hardened_malloc.git
# already have the repo? check out this version:
$ git checkout 10
      • Adds configuration variant system with two standard recommended configurations: default for an aggressive security-focused configuration and light for a more balanced configuration disabling a subset of the optional security features for better performance (comparable to glibc malloc without the thread cache) and much lower memory usage while still providing most of the security properties (details in README)
      • Switches from C11 to C17

      2 details in Everything

    Project health

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

    1. Contributors 12 +7 vs prior 12 months
    2. Maintainers 4 +3 joined · −0 left, last 12 months
    3. Bus factor 2 committers behind half the commits
    4. Community-filed 96% of issues opened, last 12 months
    5. Median time to close < 1 day first maintainer reply 0.3 hours
    6. Open backlog 31 of 171 issues ever filed
    1. Issues opened / month 0 · 0 communitymaintainers
    2. Open backlog 31
    3. Contributors / month 1
    4. Commits / month 8
    5. Stars 2,006
    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

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