CURL-CVE-2020-8285

See a problem?
Please try reporting it to the source first.
Source
https://curl.se/docs/CVE-2020-8285.html
Import Source
https://curl.se/docs/CURL-CVE-2020-8285.json
JSON Data
https://api.test.osv.dev/v1/vulns/CURL-CVE-2020-8285
Aliases
Published
2020-12-09T08:00:00Z
Modified
2026-05-18T13:46:06.783968Z
Summary
FTP wildcard stack overflow
Details

libcurl offers a wildcard matching functionality, which allows a callback (set with CURLOPT_CHUNK_BGN_FUNCTION) to return information back to libcurl on how to handle a specific entry in a directory when libcurl iterates over a list of all available entries.

When this callback returns CURL_CHUNK_BGN_FUNC_SKIP, to tell libcurl to not deal with that file, the internal function in libcurl then calls itself recursively to handle the next directory entry.

If there is a sufficient amount of file entries and if the callback returns "skip" enough number of times, libcurl runs out of stack space. The exact amount does of course vary with platforms, compilers and other environmental factors.

The content of the remote directory is not kept on the stack, so it seems hard for the attacker to control exactly what data that overwrites the stack - however it remains a Denial-Of-Service vector as a malicious user who controls a server that a libcurl-using application works with under these premises can trigger a crash.

(There is also a few other ways the function can be made to call itself and trigger this problem.)

Database specific 
{
    "severity": "Medium",
    "CWE": {
        "desc": "Uncontrolled Recursion",
        "id": "CWE-674"
    },
    "URL": "https://curl.se/docs/CVE-2020-8285.json",
    "package": "curl",
    "issue": "https://hackerone.com/reports/1045844",
    "last_affected": "7.73.0",
    "www": "https://curl.se/docs/CVE-2020-8285.html",
    "affects": "lib"
}
References
Credits
    • xnynx on github - FINDER
    • Daniel Stenberg - REMEDIATION_DEVELOPER

Affected packages

Git / github.com/curl/curl.git

Affected ranges

Type
SEMVER
Events
Introduced
7.21.0
Fixed
7.74.0
Type
GIT
Repo
https://github.com/curl/curl.git
Events
Introduced
0825cd80a62c21725fb3615f1fdd3aa6cc5f0f34
Fixed
69a358f2186e04cf44698b5100332cbf1ee7f01d

Affected versions

7.*
7.21.0
7.21.1
7.21.2
7.21.3
7.21.4
7.21.5
7.21.6
7.21.7
7.22.0
7.23.0
7.23.1
7.24.0
7.25.0
7.26.0
7.27.0
7.28.0
7.28.1
7.29.0
7.30.0
7.31.0
7.32.0
7.33.0
7.34.0
7.35.0
7.36.0
7.37.0
7.37.1
7.38.0
7.39.0
7.40.0
7.41.0
7.42.0
7.42.1
7.43.0
7.44.0
7.45.0
7.46.0
7.47.0
7.47.1
7.48.0
7.49.0
7.49.1
7.50.0
7.50.1
7.50.2
7.50.3
7.51.0
7.52.0
7.52.1
7.53.0
7.53.1
7.54.0
7.54.1
7.55.0
7.55.1
7.56.0
7.56.1
7.57.0
7.58.0
7.59.0
7.60.0
7.61.0
7.61.1
7.62.0
7.63.0
7.64.0
7.64.1
7.65.0
7.65.1
7.65.2
7.65.3
7.66.0
7.67.0
7.68.0
7.69.0
7.69.1
7.70.0
7.71.0
7.71.1
7.72.0
7.73.0
Other
curl-7_21_0
curl-7_21_1
curl-7_21_2
curl-7_21_3
curl-7_21_4
curl-7_21_5
curl-7_21_6
curl-7_21_7
curl-7_22_0
curl-7_23_0
curl-7_23_1
curl-7_25_0
curl-7_26_0
curl-7_27_0
curl-7_28_0
curl-7_28_1
curl-7_29_0
curl-7_30_0
curl-7_31_0
curl-7_32_0
curl-7_33_0
curl-7_34_0
curl-7_35_0
curl-7_36_0
curl-7_37_0
curl-7_37_1
curl-7_38_0
curl-7_39_0
curl-7_40_0
curl-7_41_0
curl-7_42_0
curl-7_43_0
curl-7_44_0
curl-7_45_0
curl-7_46_0
curl-7_47_0
curl-7_47_1
curl-7_48_0
curl-7_49_0
curl-7_49_1
curl-7_50_0
curl-7_50_1
curl-7_50_2
curl-7_50_3
curl-7_51_0
curl-7_52_0
curl-7_52_1
curl-7_53_0
curl-7_53_1
curl-7_54_0
curl-7_54_1
curl-7_55_0
curl-7_55_1
curl-7_56_0
curl-7_56_1
curl-7_57_0
curl-7_58_0
curl-7_59_0
curl-7_60_0
curl-7_61_0
curl-7_61_1
curl-7_62_0
curl-7_63_0
curl-7_64_0
curl-7_64_1
curl-7_65_0
curl-7_65_1
curl-7_65_2
curl-7_65_3
curl-7_66_0
curl-7_67_0
curl-7_68_0
curl-7_69_0
curl-7_69_1
curl-7_70_0
curl-7_71_0
curl-7_71_1
curl-7_72_0
curl-7_73_0

Database specific

vanir_signatures 
[
    {
        "digest": {
            "line_hashes": [
                "184476775510533027388718895960952159918",
                "156322506506110137926945070000429410314",
                "20670977983588760395954824366509577612",
                "278102778289078334853403258169767056118",
                "144682017389939385701608362594309706533",
                "131621475410468951009545355742511330897",
                "298680581291691322372523203432016646829",
                "87805244657659760734983676805655260028",
                "304156502825623387915031696864575794500",
                "250377572584863191851930198162220374942",
                "219152875622843895157766199396587018645",
                "249788917177248901814620531232541879609",
                "229934088363978480374866438720399817264",
                "249833688629470332671893301345845277338",
                "16616947024250621797706306804227042553",
                "163307598398905729452756516358754920690",
                "112035334574893307048913912614018044024",
                "4732401526453585347306579368991382251",
                "136748861001560477059610996662755042352",
                "196289514771246689056811597931181018401",
                "302139749805394309412029144452541212210",
                "126589822739659994475216228269045387619",
                "7052257700509419687010305017051959790",
                "95164453189720483914224746227333445313",
                "101046728775490984498669370433447595214",
                "112907376411410787337583488450866741432",
                "209725143247895220449993859528486449660",
                "161924809568114262498007302117580234034",
                "46901839399932295533444423019060590101",
                "286389445023554851020451828274250976951",
                "339243473066722259395606020902605682126",
                "193243849111261031672755347196207213838",
                "247824563245202487817546174964122985975",
                "182238994497900991494157708891485448117",
                "122276382403288479645878768147535677474",
                "260536672983422165743343616096725767095",
                "113285187455372958742317071059983421354",
                "151100951929605125895149235582978312504",
                "296780908907283281402521847979035216106",
                "245986569466214194968430266101912225619",
                "262857017288710042605982669527728268853",
                "63825592129842339935565536195935221244",
                "22260514382630545754416686415687768139",
                "272551934713781104526831918332248477068",
                "270292755082778973902658303221894869492",
                "329762068187632056024493119806360945250",
                "252400245768985037824769754995845269643",
                "176924150215363167416774373945547456578",
                "146050695021673738253830705160046071095",
                "26772898823155918896296417391003186188",
                "163938423324659538389579608420945922451",
                "335790195920982371262868827141264754275",
                "306448789986871638855997100842877346374",
                "49222901095553846119094993699932545777",
                "100957916630084887041726104581817955296",
                "99060895961864215138300934547528177110",
                "87768511433855742134055795943720903267",
                "210442911202601734021660639413709906775",
                "249815437017568467660508141034847761552",
                "35064834732799972834264501776059694593",
                "30581373627516931635570079979305687045",
                "73069935269460162140200452616170539333",
                "336889926074454307775764928034567603909",
                "80948005788548949409746454010292086251",
                "294489105666982964896093784140130784867",
                "123518199280162212681709385088815896735",
                "304114755360855681048341279394647806155",
                "339839388460226222135647677813759682259",
                "28563967063495983991498076651565504923",
                "12519712998606027190840193429206244736",
                "78733076146910625726740995148005936326",
                "113324048701480420145548900750204624198",
                "66511267095692061918534709645601427179",
                "58815775020112445308610360515692412918",
                "3355612561801615269259732278642783023",
                "257364883812737976887099773008915802416",
                "130622861614188023874674013408614909879",
                "178803334182069388137853375673130606449",
                "164603634806349293079844675328777193306",
                "69518015765548637480904078066987919762",
                "71970450577021457971319474213358522376",
                "39780458745606608704622362758242055289",
                "295862100481163884323895892161262685904",
                "67656100128756077856003049584649745349",
                "214680522712283733581818378044678819549",
                "77781875767912620221703595783849134299",
                "326341713524016072158459507011427403985",
                "63076702808956770739578637087181849397",
                "320022334904461011021002872122184754284",
                "257365936150555865064412372576098029158",
                "114329593905384646151365700732148179306",
                "335539186082343908086376234755402580280",
                "205737797643200051427201554319319933951",
                "183823347793250420801783353510962151258",
                "316015407093221385407873125741135785340",
                "235780497829215147823977033612277444840",
                "5871209694374733622750166745107985531",
                "286925292873319255277161967199864591253"
            ],
            "threshold": 0.9
        },
        "signature_type": "Line",
        "signature_version": "v1",
        "target": {
            "file": "lib/ftp.c"
        },
        "source": "https://github.com/curl/curl.git/commit/69a358f2186e04cf44698b5100332cbf1ee7f01d",
        "id": "CURL-CVE-2020-8285-65b6fad8",
        "deprecated": false
    },
    {
        "digest": {
            "function_hash": "168814935214221222596367167865072201906",
            "length": 3014.0
        },
        "signature_type": "Function",
        "signature_version": "v1",
        "target": {
            "file": "lib/ftp.c",
            "function": "wc_statemach"
        },
        "source": "https://github.com/curl/curl.git/commit/69a358f2186e04cf44698b5100332cbf1ee7f01d",
        "id": "CURL-CVE-2020-8285-a42d2256",
        "deprecated": false
    }
]
source 
"https://curl.se/docs/CURL-CVE-2020-8285.json"
vanir_signatures_modified 
"2026-05-18T13:46:06Z"