DaystoPatch

CitrixExploited incident

NetScaler ADC and Gateway out-of-bounds memory read ("CitrixBleed 2")

CVE-2025-5777, CVE-2025-5349Critical, CVSS 9.3In CISA's Known Exploited Vulnerabilities catalog since 10 Jul 2025

  • Exploited after a fix existed
  • Known ransomware use
FixedFixed for every supported version on the day it became public.

Response

Silence
0h
First public report to first vendor statement
Exposure
same day
First public report to first fix
Follow-through
same day
First public report to a fix for every supported version
  • Vendor silent
  • Vendor statement, no fix
  • Fixed for some versions
  • Fixed when disclosed
  • Date only, no time of day

Timeline and evidence

Open a moment to see its source and archived quote.

  1. First public report

    CVE record CVE-2025-5777 (CNA: NetScaler)CuratedQuote verified

    "datePublished":"2025-06-17T12:29:34.506Z"

    Coordinated disclosure with fixes. ReliaQuest assessed likely exploitation on 2025-06-26; later reporting put exploitation from mid/late June 2025, after the fix.

    Recorded time
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    Curated. Found by a researcher, with a verbatim quote and link.
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    Found in the archived copy
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    sha256:96b4b40f775fe5ad…
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    7 more sources for this moment
    Citrix advisory CTX693420ClaimedQuote verified17 Jun 2025

    NetScaler ADC and NetScaler Gateway Security Bulletin for CVE-2025-5349 and CVE-2025-5777

    The vendor's own disclosure.

    Source
    Citrix advisory CTX693420 vendor advisory
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    sha256:775ec3f92b69993a…
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    CVE.org record CVE-2025-5777ClaimedQuote verified17 Jun 2025, 12:29 UTC

    Insufficient input validation leading to memory overread when the NetScaler is configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server

    CVE record published.

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    sha256:96b4b40f775fe5ad…
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    Bluesky postClaimedQuote not checked yet17 Jun 2025, 12:57 UTC

    You can now share your thoughts on vulnerability CVE-2025-5777 in Vulnerability-Lookup:

    Earliest third-party post we hold.

    Source
    Bluesky post social
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    Not checked yet
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    Mastodon postClaimedQuote not checked yet18 Jun 2025, 13:30 UTC

    📢 Vulnérabilités critiques découvertes dans NetScaler ADC et Gateway 📝 Selon ce bulletin de vulnérabilité de Citrix... 📖 cyberveille : https:// cyberveille.ch/posts/2025-06-1

    Earliest third-party post we hold.

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    Mastodon post social
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    Hacker NewsClaimedQuote not checked yet7 Jul 2025, 17:26 UTC

    CVE-2025-5777: CitrixBleed 2 Exploit Deep Dive

    Earliest third-party post we hold. An independent author on another platform posted within 48 hours. Used for unreviewed incidents only, never graded.

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    Hacker News hn
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    CISA KEV (CVE-2025-5777)ClaimedQuote verified10 Jul 2025

    Citrix NetScaler ADC and Gateway Out-of-Bounds Read Vulnerability

    Added to CISA's KEV catalog on 2025-07-10.

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    sha256:ef8fffede5c47200…
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    Research: greynoiseClaimedQuote verified16 Jul 2025

    Exploitation of CitrixBleed 2 (CVE-2025-5777) Began Before PoC Was Public

    Earliest mention we hold (a vetted outlet).

    Source
    Research: greynoise research
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    sha256:1037703b81576029…
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  2. Vendor statement

    at disclosure

    CVE record CVE-2025-5777 (CNA: NetScaler)CuratedQuote verified

    "datePublished":"2025-06-17T12:29:34.506Z"

    Recorded time
    Precision
    To the minute
    Origin
    Curated. Found by a researcher, with a verbatim quote and link.
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    Found in the archived copy
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    sha256:96b4b40f775fe5ad…
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    Yes
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    3 more sources for this moment
    Citrix advisory CTX693420ClaimedQuote verified17 Jun 2025

    NetScaler ADC and NetScaler Gateway Security Bulletin for CVE-2025-5349 and CVE-2025-5777

    Source
    Citrix advisory CTX693420 vendor advisory
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    Claimed. The date the source gives.
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    Found in the archived copy
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    sha256:775ec3f92b69993a…
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    Citrix bulletin CTX693420CuratedQuote verified17 Jun 2025

    2025-06-17 Initial Publication

    Source
    Citrix bulletin CTX693420 vendor advisory
    Recorded time
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    Origin
    Curated. Found by a researcher, with a verbatim quote and link.
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    Found in the archived copy
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    sha256:775ec3f92b69993a…
    Used in metrics
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    Citrix advisory CTX694788ClaimedQuote verified25 Jun 2025

    2025-06-25 Initial Publication

    From the advisory's revision history.

    Source
    Citrix advisory CTX694788 vendor advisory
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    Claimed. The date the source gives.
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    Found in the archived copy
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    sha256:f379c1eb8498264d…
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  3. First workaround

    No official mitigation found yet.

  4. First fix

    date onlysame day

    Citrix bulletin CTX693420CuratedQuote verified

    NetScaler ADC and NetScaler Gateway 14.1-43.56 and later releases

    Later changelog entries (2025-07-25 blog link; 2026-07-20 formatting) do not change fixed versions.

    Source
    Citrix bulletin CTX693420 vendor advisory
    Recorded time
    Precision
    Date only (no time of day is shown)
    Origin
    Curated. Found by a researcher, with a verbatim quote and link.
    Quote check
    Found in the archived copy
    Snapshot
    sha256:775ec3f92b69993a…
    Used in metrics
    Yes
    Dispute this timestamp

  5. Fixed for all versions

    date onlysame day

    Citrix bulletin CTX693420CuratedQuote verified

    NetScaler ADC 12.1-FIPS 12.1-55.328 and later releases of 12.1-FIPS

    Fixes for 14.1, 13.1, 13.1-FIPS/NDcPP and 12.1-FIPS at publication; non-FIPS 12.1 and 13.0 are end of life.

    Source
    Citrix bulletin CTX693420 vendor advisory
    Recorded time
    Precision
    Date only (no time of day is shown)
    Origin
    Curated. Found by a researcher, with a verbatim quote and link.
    Quote check
    Found in the archived copy
    Snapshot
    sha256:775ec3f92b69993a…
    Used in metrics
    Yes
    Dispute this timestamp

Send this to your boss

No brief for this incident yet. We write one for every open incident and every critical bug exploited before a fix.

Affected products

  • NetScaler ADC
  • NetScaler Gateway
  • NetScaler ADC FIPS and NDcPP
How we built this timeline

Bulletin CTX693420 also fixes CVE-2025-5349 (improper access control on the management interface, CVSS 8.7). Citrix initially disputed exploitation claims (ReliaQuest, 26 Jun 2025); public PoCs appeared in early July and CISA added CVE-2025-5777 to KEV on 10 Jul 2025 with ransomware use Known.

Exploitation began after the 17 Jun 2025 fix, so exploited before a fix is false; Citrix advised killing all ICA/PCoIP sessions after upgrading because stolen session tokens survive the patch.

CVSS v4.0 9.3.

Related

Citrix report card